In general, and this seems to be agreed upon, best use you'll make out of characters when you get all mediums is the following:
Ginny towards tanking. She's fast enough to outpace most enemies without any mediums, and is pretty much faster than 99% of the bosses already, where she'll be healing most of the time. Taking her down this route gives a few side benefits that make it even more appealing, like giving her Zephyr for the first turn nukings of randoms (even without magic boosts, Zephyr hits like a truck on PCs not Jet), more HP to abuse Valiant with, and lots of stat buffers for things to do when she's not healing.
Clive towards physical damage; freaking obvious it hurts. He's the one character whose Physical damage is actually worth noting cause its so much better than everyone else's, and his base accuracy being really good to boot means he won't have to worry about wasting any boosts (he'll want 2 Bullets, admittedly, so he can use Gatling since it can be more efficient than Lock On in some cases. Also, more Bullets = less turns spent reloading.)
Gallows towards magic; also really obvious! Actually, Aqua Wisp/Lust Jaw/Love Charm combo was pretty much MADE for him. Gives Extension Heal, Weakness PS with 3 Elements to play with (Water, Darkness and Ice), Weaken spell to back up Weakness (and again, 3 elements means you can pretty much always put a weakness on SOMEONE, since Weaken fails on those who naturally resist that Element in some manner.)
This leaves Jet with all the left overs...might as well build him towards speed so you have a second character who always goes first, making him a good item boy. If you build Gallows and/or Clive properly, Replay does some pretty brutal things, effectively, transforming Jet's worthless turn into a means to double Clive or Gallows damage.
Of course, this isn't to say there are other effective ways to go, but this really feels like the best to me!
Anyway...
SONIC PLOT!!!: In the middle of Chapter 2.
Game is showing potential, though one thing that is clashing with me is my ability to pull off POW moves. Most particular, the timed hits one. Rapid presses and following the circle ones I can do, but I always seem to fuck up the timed hits. Thankfully, Items don't use that so it usually accounts for only support skills (which...it sounds like Items can make up to some extent), and damage moves.
Otherwise, battle system is kind of neat, map screens lacking true randoms, instead going the route of "You can see enemies, though some respawn!" makes it so you don't get annoyed when trying to figure out puzzles, etc.
Also follows suit from SMRPG in that the game likes to capture random aspects from the home game to give a feel that its a Sonic game. By which I mean, in SMRPG, Mario could jump, there were platforming puzzles, Chests were like boxes, what have you; it gave off a Mario feel!
Here, they do things that fit Sonic; there are random loops to run through, springs to jump on, rings are scattered around for no good reason, what have you.
This mostly shows they took their time to make it an actual splicing of Sonic and an RPG, not just "hey, its an RPG, WITH SONIC CHARACTERS!!11!!11"
Anyway, game looks promising enough...no, its not likely to become this almighty godly game, but if things continue the way they are, it should be somewhat enjoyable, and nice fluff game.