Regarding the Sonic, Sonic, and Sonic team, the important part would be easy visual distinguishing. If you went with Boom Sonic, for an example, it can't just be Sonic 3 Sonic with bandages, it needs to look visibly different. Sonic 1 Sonic, Sonic 3 Sonic, and Shinbs' Sonic seems like it might work, to me.
VAdaPEGA's Boom Sonic is, in many respects, visually closer to S1 Sonic than to S3&K Sonic. So S3&K Sonic, Shinbs' Sonic and VAdaPEGA's Boom Sonic are as distinctive as those. It also helps in super form, as I can base the Boom Super Sonic on S2's Super Sonic.
Sure, you can even go further and have Boom Sonic, Riders Sonic, Sonic Sonic, but the important part, imo, would be to edit each design from a visually separate sheet.
Possibly not, although 3 is your best bet. The Sonic Boom one sadly looks more like a zombie version of Sonic 2. And classic might work better if it had a ligher shade of blue. But honestly I'm not entirely sure this is a good plan - I don't think there's enough you can do at that resolution to make them distinguishable, particularly when it comes to jumping/rolling.
If by Classic you mean S3&K, it is the exact same one already used in SCH. In any case, the extra shade of blue is not going to happen because of palette limitations: there are no palette entries available.
I can get that this hack wants to be unique, but ignoring anything relating to 'it wasn't in the original' is strange for a hack with nothing but S1/S2 levels in it. In fact, a lot of the feedback I've heard of this hack describes it as 'the definitive S1/S2', but maybe I shouldn't have let that decide my expectations. Still, with all this talk of options and teams, is it too much to ask for a Team Original? It can't require anywhere near as much effort as a team of entirely new characters.
It might be too late to give ideas for Team Generations, but I'll say this anyways. In place of Sonic Boom Sonic, how about Sonic Advance Sonic? Advance Sonic looks very distinct, even when spin-dashing or jumping, and there are some cool mechanics you could add too. For example, when you get launched into the air by means of springs or ramps (but not jumping) pressing the B button and a direction at the same time would make Sonic do a trick move to gain some extra air time or something like that, and pressing C makes him do the insta-shield like normal. I suppose the only problem with Advance Sonic might be the palette or sprite size, but I still think the idea sounds cool.
Regarding the change in character physics - I don't mind this at all. Characters in the Genesis games control like bowling balls and are exceedingly sluggish when doing precision platforming or fighting bosses. Spin dashes are mandatory to get up most slopes from a standstill, which, while making technical sense, isn't fun if you don't know the stages inside and out. Making certain characters uniformly faster would help, but another, potentially less game-breaking alternative would be to tighten up low-speed acceleration. (Perhaps that's something to consider for Tails if you're thinking of a way to modify his stats?)
I certainly prefer the first one, but I'm not a fan of the pose you decided to use for the standing sprite. In my opinion, this one sprite from the sheet would fit in better: I'm still not a fan of #3. Whenever I look at the sprite sheet, I can't get over how inconsistent and stiff his animations are and the fact that there are a lot of sprites in the sheet where Sonic's head suddenly has longer spikes and seems to lose a lot of his shading. And... his head... he hardly ever moves his head, and when he does, it feels like his facial structure shifts entirely. Here's the Mod Gen Sonic, for anyone who has yet to see it. Both animations are based on the Sonic 2/3 walking animation, but I cannot get over Mod Gen Sonic's head movement.
Hm, now that you point this out, I can't unsee it in the sheet Also, that version seems more complete (but not better) than the one I have here.
If your still looking for team ideas, what about Hyper Metal Sonic (Sonic CD Metal Sonic *Gets Insta Shield, in the form of his Black Shield sprite*), Silver Sonic (Sonic 2 *can perform a dash jump, think Flame shield) and Mecha Sonic (Sonic 3 & K (can perform double jump? maybe could fly using his super form sprite, just keep the color the same as his normal form) Or just Mecha Sonic with anyone and I would be happy lol
It'd help make the three characters more distinctive. As a side note, how do Chaotix characters compare stats-wise? Also didn't Sonic 3 multiplayer have higher acceleration for Tails? (along with higher top speed for Sonic - see, there's precedent for this stuff!)
Espio has the same stats as Tails and Knuckles, Charmy and Vector are slightly slower and have slightly smaller acceleration. In the current release, spindash has the same speed for all teams, but the next version will have team-based spindash speeds.
Team robo-sonic is also a good idea, I couldn't figure out why would they reveal to Eggman, and then who will you fight against at Death Egg? I mean, 2 Silver Sonics, that's a main problem with it. Regarding to #1, #2 or #3, I also prefer #1, but at this point I lost the track at what are you considering or not. I would use this standing sprite though As for team original, I can always give you my characters if you can wait to 2065. Edit: I can't get the bloody emoticons working...
I have, yes. I already have Metal Sonic's sprites (courtesy of Lone_Devil), I just need the Metal Knuckles and Tails Doll sprites.