Heath: I've made a new category for game mechanics. One is more general, like "are character intros back" or "are there star KOs?" The other one is for more technical questions, like "Is momentum from running jump maintained" or "can you attack during ledge jumps?"
BTW smashgaf, I'll easily be able to answer the general mechanics questions based off footage/trailers, but I will ABSOLUTELY need your help to answer the TECHNICAL questions. I don't know that i'd be able to answer most of them by just looking at footage. Please feel free to help me answer them.
Updated Set of questions:
Character Questions (non-technical)
Final Smash for Mario
Final Smash for Link
Final Smash for Olimar
Final Smash for Zelda
Final Smash for Pikachu
Final Smash for Marth
Final Smash for Fox
Final Smash for Sonic (likely the same)
Final Smash for Zero Suit Samus
Final Smash for DK
Final Smash for Bowser
Wii Fit Trainer's Kirby Hat
Rosalina's Kirby Hat AND power (Olimar's Neutral B is summon pikmin, but Kirby's Olimar power is to throw a random pikmin)
Little Mac's Kirby Hat AND does kirby gain a KO meter?
Mega Man's Kirby Hat
Greninja's Kirby Hat
Villager's Kirby Hat
Olimar's Kirby Hat power - Does it throw pikmin in order?
All Taunts for Little Mac
All Taunts for Rosalina
All Taunts for Mega Man
All Taunts for Greninja
All Taunts for Wii Fit Trainer
All Taunts for Villager
Any new taunts for playable veterans
Luma colors? Why is it sometimes a different color? Random?
All villager variations (all boy versions, all girl versions)
Character-specific technical questions
Is Bowser's Koopa Klaw still be influenced by the person who is grabbed when they have lower % than him and vice versa.
Does Bowser's crazy forward b -> air dodge infinite double jump trick still work?
Does Dedede still have a chainthrow?
Will DK have a mid air down special?
Can Kirby do his f throw combos at low percents?
Is Link's dAir meteor smash worthwhile? Is it still a meteor smash, like it was claimed on the dojo?
How easy/frequent is it to fill Little Mac's KO meter?
Does Marth's down throw -> tipper fsmash guaranteed combo still work at very low percentages?
Is Marth's grab release still viable? Can he ground grab release -> regrab on any characters? Can he air grab release -> fair on any characters? etc.
Can Mega Man and Sonic air dodge after their Up Bs?
Does pikachu still have his down throw chain grab?
Does Pikachu still have his forward throw chain grab?
Can Pikachu still quick attack cancel?
Details on Rosalina’s Luma's mechanics. How does it behave, particularly when left alone? We have assumptions but no concrete facts. How much health does it have before it disappears? 1 hit? 10%? 50%? Is it based off rosalina’s percent in any way?
Does Samus' bomb (down+B) explode on contact(melee), or on a timer only (brawl)?
Sonic's Homing Attack - can you still stall under the stage when someone is within his homing range?
Mechanics of Villager's Down B (what happens when you use Down B and already have a tree out somewhere else)
What are Wii Fit Trainer's Deep Breathing Mechanics? Is it timed? Does it buff all attacks/specials? How big is the buff? Is it just percentage, or knockback, or both?
Why does Zelda's Phantom Slash have 2 different types of slashes? Does it just just depend on how long you charge it?
How does Zelda's Phantom Slash work in the air? Can you charge it?
Item Questions
How does the Beetle item work? Does it pull people off screen?
Who does the Blue Shell target? Most stock? Smallest percent?
What is the chest item? Is it just another container (like box or barrel?)
How does Cucco item work? Does it have to be hit? What happens when it triggers?
How much percent does fairy heal?
Is gust bellows useless? Is it like fludd?
Are there any assist trophies in the demo that weren't in Smash Direct/Dojo?
Are there any pokeballs in the demo that weren't in Smash Direct/Dojo?
What does the P Flag do?
What do the Galaga bugs do?
Can you attack with the Super Leaf/Raccoon Tail?
Stage Questions
How many transformations does Mushroom Kingdom U have?
How many transformations do the colosseum have?
How many transformations does arena ferox have?
How many enemies are there in reset bomb forest?
How long until reset bomb forest restores to a non-scrolling version?
Are any returning stages different (other than visuals?)
Is the Dark Lord a boss or a stage hazard on find mii?
Do the blocks change shape while you're playing in the living room, or do they spawn when you start the level?
Do pokemon make an appearance in prism tower, or is it just a visual of the city?
Can you knock the lights down in the boxing ring on 3DS, or is this a wii-u-only feature?
What happens when the bomb train hits you/the train in the spirit tracks stage?
Are you on a plane 100% of the time on the pilotwings stage?
Do you go through the volcano in the pilotwings stage?
Do pokemon appear in the kalos leage stage?
How many different rooms are there in the kalos league stage? Is the room determined at start, or does it change mid-match?
If Pyrosphere is playable, what are Ridley's Boss mechanics?
Do any other stages have stage bosses?
Technical Mechanics
How does the ledge mechanics work? Is it based off higher or lower HP?
Can you cancel the tether latch by pressing down and then do another tether immediately after?
How many tethers you can you do (in Brawl, you could do a max of 3 tethers)?
how soon can you jump from the ledge (aka doing a ledgehop)?
Can you attack during ledgejumps (as in when you press a jump button while on the edge) and/or do anything else during ledgejumps?
Is rolling onto the stage is possible to be used as an edgehog (doubtful but it could have a little more occupancy than Brawl, you never know)?
Is edgehogging a legitimate strategy still?
Do grabs restore character's jumps? Test to see if grab releasing chaingrabs are still in the game (and if they are, this isn't good lol).
Is momentum from a running jump maintained?
Do attacks still have tripping properties? (try this with Zelda's Down Tilt or even Bowser's Forward Tilt). If so, is it random chance or guaranteed?
Are any Brawl techniques are in the game still such as DACUS (Dash Attack Canceled Up Smash), Glide Tossing, RAR (Reverse Aerial Rush, the tech you use to turn yourself around as you're going into the air), etc?
Can you air dodge more than once in the air. Also test out how long air dodge invincibility lasts and how punishable they are vs Brawl.
Compare spot dodges, see how long they are invincible and if you can spam them as much as you can in Brawl.
Test out shield drop lag (if there's any at all) as well as if there's any shieldstun (Brawl didn't have any shieldstun which made shieldgrabs super powerful at the beginning of the metagame).
Can you dash dance? Is it useful?
Can you cancel your run with a crouch?
Can you still do the quick ledge grab like in Brawl?
Is glide tossing still in the game? If so, do characters still glide as far as they do in Brawl?
Is it possible to DI moves at lower %s?
What are grab/grab release mechanics like?
What determines the number of invincibility frames while grabbing the ledge? percent?
Can characters snap to the ledge in the middle of their up b (not just at the end)?
How easy is it to grab items in the air/while running? Brawl easy or melee hard?
General Mechanics
Are character intros back? (Mario Warp Pipe intro for an example)
Do certain moves still "freeze" time, like Zelda's sweet spot forward air or the multi-hit Pikachu down smash?
What are the alternate colors for every character in the demo?
Do alternate costumes, like Male Wii Fit Trainer, also have alternate colors?
How many taunts do characters have? What are they? Do veterans differ from Brawl?
Are star KOs in the game?