Regarding "First Quest" options...
Yeah, even if you follow it to the letter.. at best "Mentor" can save three heroes from dying permanently (but they might only get 1 BP back since these are 1d6 healing potions, not instant 4's like the EU edition... keep in mind the NA deck includes only THREE potions of healing, while if you recall the EU deck had two) since he can do so after the fact rather than requiring to have the potion... the four heroes still have high percent chance of failing this quest, again and again. Wouldn't mind seeing HispaZargon or anybody else with their own "difficulty calculator" run through it, but I imagine that will back up my suspicion here even though I haven't playtested it myself.
To their credit, they did make a small correction via the public playtest for Rogar's Hall, but the only fix was to note the proper placement of secret door G that was missing from the very first posting.
Using healing spells, that's two more saves, at best, but remember the spells only restore up to 4 (can't go over maximum if they're healing a living hero). Of course you'll need the Dwarf to disarm traps, and if he dies you're left trying just to JUMP them (and since you lack the Rabbit Boots or any special potions, there is a 50% chance of failure on those pits which then become permanent hazards in the game if you ever do need to backtrack).
It is designed to be this way! Of course the base rules state then in the case of a total party kill (or any failure to complete a quest) a replay of the quest should require that the quest be re-arranged next time to prevent memorization.
Then again if you just have the heroes play the quest once (which will either be short if they lose, or very long if they win... nearly double the time of a standard game system quest)... whether they win or lose, and then move on, that seems the least frustrating way to use it. I don't personally recommend it for most gaming groups played without changes.
For reference, Rogar's Hall has
57 Monster BP (closer to the difficulty of the EU "Dark Company" from "Advanced Quest" or in the range of EQP difficulty), plus multiple traps. The Wandering Monster is a goblin, but they're special goblins that have a chance to do higher damage. PLUS the bad guy gets a random "Dread" spell (which could be pretty nasty... imaging if it were firestorm, cloud of "dread" or summon undead).
The Trial, by contrast, has 35 Monster BP overall (and Orc as wandering monster), with no traps (hazard cards from searches are still possible of course). And as we all know, the NA edition of the Trial has been a notorious TPK quest, especially for young first-time players.
If Rogar's Hall is just a one time demonstration of how hard the game can be... great. If you expect the heroes to win it (and play it OVER AND OVER until they do), I think they should be given more help than what they're given by default. It feels more experimental than a real quest to me, as is, especially for young first time players who may be overwhelmed by the extreme difficulty and not understand why they're supposed to lose after all that effort.
If you want a very easy first quest, play "the Maze" (with only SIX monster body points, not counting Wandering Monsters) although it doesn't teach you about teamwork, it's more competitive and may be fun for younger heroes. Training quests are fine (the EU first edition has those "one room goblin deathmatch" scenarios in its instruction booklet that do that), and the idea of role playing Mentor getting the heroes ready for their journey is a cool idea, but the fact is that for many of us we're either playing a rare game that was hard to get together with adults... or we're playing with small children who are learning to be better players. Neither of those demographics I think take well to the basic layout of Rogar's Hall, again, respect to Stephen Baker but this one just doesn't work well, in my humble opinion. If you're so good that you beat it easily, then you are a super player (or cheated).

One way you could make Rogar's Hall easier (but much longer, potentially) is to assume (as Stephen Baker did when making it, since he included the Mentor figure, which otherwise would be the generic stand-in of the Chaos Warlock/Dread Sorcerer gray figure), is to have it played with more than four heroes.... throw in the Bard, heck, have the Druid and Warlock play too! Then it would at least have the benefit of more firepower for all those extra monsters. Do you have the Knight? Let him/her play! Granted, if those are being controlled each one by a human player, that's a pretty crowded game, but you need all the help you can get if you change nothing else! (and now there will be less healing to go around, but at least the new heroes have their own ways of healing or saving from death too).
Fixing Rogar's Hall could take many forms. One would be to flip back to the EU's body point rules (maybe this was what Baker was originally thinking when he wrote it?) so that each monster only has 1 (Fimirs, Gargoyle, Chaos Warriors and Mummies become more manageable!) and this drops the overall monster BP total to 37.
Another would be to say that instead of using the actual cards, just say each hero can be restored ONCE to Full BP after dying automatically, via Mentor's training powers or whatever, and then leave the rest to the actual spells (you could also leave the Healing Potions in the Treasure Deck to be found and possibly used as even more healing).
Or you could delete about half the monsters... which would also halve the time it would take to "win" the quest.
For another contrast, "The Trial" in the EU 2nd edition (1990) had 26 Monster BP (not counting Wandering Monsters) but stipulated that ONLY the only cards used that quest were the Monster Cards. So yes, the monsters all had only one body point (and the monster distributions were different than the NA edition) but no treasure deck means no wandering monsters, but also no gold or potions, and no spells means the wizard is extra vulnerable. But then in that version the shortsword also could attack diagonally by default, so there's your door blocking strategy right there, something not possible in the NA edition until you get the staff and/or longsword.
The Japanese game system had a remarkably easy first quest (under the first stage "beginner" rules), where the only magic was "first aid" that the Magician (Wizard) could use as many times as desired (but only healing 1 BP per turn to himself or another hero) and only 8 monster BP (Wandering Monsters in this edition can't be fought anyway, they make an unblockable attack once and then vanish, with one of five possible monsters depending upon the card if I recall correctly).
So Japanese first quest is probably the easiest, EU 1st edition The Maze is also a very easy choice (Orcs still have only one BP under the NA rules if using Phoenix's adaptation). Next The EU Trial is quite a bit harder. New Beginning is easier in some ways than the NA Trial (less monster BP, more rewards) but harder in others (harder boss fight, traps present). Then the NA Trial, and lastly Rogar's Hall ranks up there with some of the more difficult official quests as written... because it wasn't designed to be won. And of course Solo Quests for the Elf and Barbarian Packs are very broken, ranking up there in difficulty not so much for the overall monster BP (although those are high) but the sheer number of things that can go wrong (traps, unwinnable fights with Yeti, scarcity of healing, etc). So EQP 1 has 17 monster BP but the wandering monster is a mummy. BQP 1 has 35 monster BP (and wandering monster is once again 2 BP). Both of these require some tweaks to prevent multiple attempts after dying since intended for a brand new player.
The Dave Morris novels include some solo quests ("A Growl of Thunder" in Tyrant's Tomb and "Running the Gauntlet" in Screaming Spectre), that aren't necessarily meant as "first quests" but certainly could be, and those are much easier in comparison because you actually can find a powerful companion to help you (or if you get lucky, a shortcut will let you beat it before you even need them!).
Growl of Thunder (EU rules = 25 monster BP; NA rules per phoenix = 39 monster BP) Barbarian solo can get a Wizard NPC to help (4 BP, 1 attack die, Water & Earth spells, so he could heal up to 8 BP!).
Running the Gauntlet (EU rules = 12 - 24 monster BP depending upon his choices; NA rules per phoenix = 21 - 37 monster BP; depending upon his choices!) Wizard solo can get a standard Barbarian NPC to help (8 BP, 3 attack dice, but charges 50 gold every time he loses 1 BP). It's possible to win this quest under the NA rules only fighting 6 BP worth of monsters AND getting all his used spells back!). In the EU original, you can do the same only facing 4 BP of monsters.
So these two are a little different I will admit. The first "group quest" for the Remake should either be The Trial, the Maze or New Beginnings, in my humble opinion. Skipping the Trial misses a rite of passage though for the classic game! The Maze will be missed by nostalgic EU players from '89.
In the end, most people will just play "The Trial" since it's the first quest, and they aren't going online to the fan community looking for alternate quests from the past or even the alternates proposed by Avalon Hill writers before they play.
Yes, adding these to the Companion App could help people learn about their options.