I was bored last night so I thought extensively about an isaac/felix moveset.
Also thought of the costumes, so let's start with that.
Best case scenario, Isaac's 4 first costumes are just colors for him and his team, then we have Matthew and his as an alt. (like Cloud's alt, Ike's alt, Mario's alt, Bowser Junior's alt, Bayo's alt etc etc)
For Felix, same deal expect his alt is just him with his mask on and taking colors of the first bad guys (so him, Saturos, Menardi and Alex).
Ok that's it for costumes.
Now Isaac's moveset. It all depends on one thing, does he has his sword out or does he keep it sheated like Shulk ? Would mostly be visual flavor i think.
Since we never saw isaac with his sword out on an official artwork, I'll use what we saw him use canonicly in game: longswords. That's what he has in DD and his signature weapon is a longsword. Probably won't be as big as buster sword etc, but we can assume it would be equivalent to the master sword, but used with both hands.
Jab: Downward slash, followed by an upward one placing him in his cast stance, third part is quake or vine, working similar to Robin's wind, but slowly pushing the opponent away rather than upward. In an angle i'd say.
S-Tilt: His sword strike from DD, a wide downward strike in front of him.
D-Tilt: Ground, buried opponent around Isaac. If his sword stays sheated most of the time, could make him take his pose from the boxart
U-Tilt: Upward slash.
S-Smash: Ragnarok. Same concept as Bayonetta's Smashes. Transmutation circle behind his shoulder as his strikes.
D-Smash: Quake. Stone pillars launching straight up.
U-Smash: Spire Growing around him before bursting at the tip of his sword. Would have the same functionning as Roy's U-Smash.
Dash Attack: His classic attack animation, jumping forward while striking.
N-Air: (if sword sheathed) Pommel strike forward and kick backward. (if sword in hand) a spin on himself holding it with two hands (the critical spin attack from DD)
U-Air: Scoop, can juggle
F-Air: Forward stab with multiple hits (centurio critical hit from DD)
B-Air: Slap
D-Air: Meteor Strike (angled forward)
Grab: Catch Can tather recovery
Pummel: exactly what Master hand does when grabbing you, they like using it for isaac hands so why not continue?
Up Throw: Lift
Back Throw: Pull (from DD)
Forward Throw: Force
Down Throw: Pound
Special: I guess Move. Shields from projectiles and doesn't do any damages, but stays on field long enough for Isaac to iniatiate movement after casting it.
U-Special: Retreat, works like most teleportation moves (zelda, mewtwo)
Side Special: Bamboo spear. Long range stab. Sweetspot at the tip. Kinda similar to Corrin's side B, maybe without the grab effect, though it could work.
Down Special: Reveal/Mind Read. Read through the opponent's mind to counter their attack ! (kidding kidding) Gaia (chargeable) Explosion around isaac, doesn't do much damage by itself but lifts the targets upward with several hits.
FS: Judgement. Area in front of isaac catches opponents, starts cutscenes and the big explosion takes place in that area and expands a bit.
That's it for Isaac ! Next up is Felix, as an echo i won't have to cover as much stuff.
Main difference would be that his sword has smaller reach and he uses it with one hand, but strikes harder on most attacks, sometimes because of multi hit. But since he has less reach and would have more recovery on his attacks he is easier to punish.
Jab: Similar to link's exept the third his is using thorns for a similar effect to isaac's jab.
S-Tilt: Upward slash in from of him.
D-Tilt: Petra, in front of him only, paralyses for a few frames.
S-Smash: Odyssey. Two smaller swords hit succesively, holding the target in place before Felix charges through them for the final hit, makes him travel some distance so if dodged could be very easy to punish.
U-Smash: Thorns, same as Isaac it's just visual flare.
Grab: Same, but cannot tether.
Special: Move is the same.
Up Special: Sand. Similar to lucario's recovery, but makes him immune to physical attacks and allow to pass through opponents. If he lands on the ground he recovers immediatly. If he's in the air he is vulnerable while reforming himself (you can still hover slightly for the few frames it takes).
Side Special: Like Isaac's but with thorns instead, smaller reach but multi hit (kinda like a drill) and higher damage, without sweet spot.
FS: Catastrophe. Jenna appears further and summon's a transmutation circle with Felix, functions like Judgment. But does electric damages rather than energy.
Pfew, i think that's it for now. Thanks for ready folks.