So I'm nerding out in the training room (while waiting for pc parts to arrive so I can actually play >_<) and started making a list of Impostor character-specific combos. Posting what I have so far (the left half of character select screen). I tried to make them all relatively easy to do, but I'm sure there's still some hard ones in there. Bigger problem I think is that it's a lot to memorize and I didn't really go out of my way to make the combos similar to each other. I'll probably continue this later unless someone beats me to it and maybe go back through and try to make the existing ones a bit more homogeneous if I don't get absolutely sick of making Impostor combos by then.
UPDATE: Added rest of cast and changed/added a few of the older combos.
KUNG LAO:
Mid-screen:
112 xx db+1, 312 xx db+1 [24%]
112 xx db+2 (3 hits~EX), dash, njp, f+2 xx db+1, f+2 xx db+1 [29%]
njp, 112 xx db+1, 112 xx db+1 [24%]
air-to-air jp, f+22 xx db+1, 112 xx db+1 [21%]
Corner:
312 xx db+1, njp, ji3, 112 xx db+1 [31%]
112 xx EX bf+1, 112 xx db+1, njp, f+3 xx db+1 [36%]
312 xx EX bf+1, 112 xx db+1, njp, 1 xx db+1 [37%]
112 xx EX bf+3, 22 xx db+1, njp, f+3 xx db+1 [33%]
njp, ji3, 22 xx db+1, 22 xx db+1 [25%]
JAX: (ground pound unblockable reset during mimicry stagger)
Mid-screen:
db+1~b, njp, ji3, f+22 xx db+2 [33%] (damage boost)
Corner:
db+1~b, d+2, 112 xx bf+1 [37%] (damage boost)
db+1~b, d+2, 112 xx EX bf+1, d+1 xx bf+3 [43%] (damage boost)
KENSHI:
Mid-screen:
112 xx db+1, d+1 xx db+1 [19%]
112 xx db+1, d+1 xx db+2 (3 hits~EX), run f+2 xx db+1 [29%]
njp, db+1, d+1 xx db+1 [16%]
Corner:
112 xx db+1, d+1, 112 xx db+1 [25%]
njp, db+1, d+1, 112 xx db+1 [21%]
KITANA:
Mid-screen:
112 xx db+1, walk forward, njp, 112 xx db+1 [22%]
112 xx db+2 (3 hits~EX), dash, njp, f+22 xx db+1, 22 xx db+1 [30%]
njp, ji3, f+22 xx db+1, 22 xx db+1 [21%]
air-to-air jp, f+22 xx db+1, walk forward, njp, f+3 xx db+1 [19%]
Corner:
312 xx db+1, njp, ji3, 112 xx db+1 [27%]
112 xx EX bf+1, d+1, d+1, 112 xx db+1, njp, 22 xx db+1 [35%]
312 xx EX bf+1, d+1, 112 xx db+1, njp, 22 xx db+1 [38%]
112 xx EX bf+3, d+1, 112 xx db+1, njp, 22 xx db+1 [33%]
njp, ji1, ji3, 113 xx db+1, 22 xx db+1 [24%]
SCORPION:
Mid-screen:
312 xx db+1, njp, ji3, f+22 xx db+1 [25%]
312 xx db+1, ji1, 312 xx db+1 [25%]
312 xx db+1, jip, 112 xx db+2 (3 hits~EX), f+22 xx db+1 [30%]
112 xx db+1, jip, 112 xx db+2 (3 hits~EX), dash, njp, f+22 xx db+1 [29%]
112 xx db+2 (3 hits~EX), dash, njp, f+2 xx db+1, ji1, 312 xx db+1 [31%]
njp, ji3, f+22 xx db+1, ji1, 312 xx db+1 [25%]
air-to-air jp, f+22 xx db+1, ji1, 312 xx db+1 [21%]
Corner:
112 xx db+1, njp, ji1, ji3, 112 xx db+1 [24%]
312 xx db+1, njp, ji1, ji3, 112 xx db+1 [27%]
112 xx EX bf+1, d+1, 112 xx db+1, njp, 22 xx db+1 [34%]
312 xx EX bf+1, 112 xx db+1, njp, 22 xx db+1 [36%]
112 xx EX bf+3, 22 xx db+1, njp, 22 xx db+1 [32%]
njp, ji1, ji3, 112 xx db+1, jip, 312 xx db+1 [26%]
ERRON BLACK:
Mid-screen:
njp, db+1, run f+22 xx db+1 [18%]
Corner:
312 xx db+1, njp, ji3, 112 xx db+1 [32%]
njp, db+1, ji1, ji3, 112 xx db+1 [24%]
ERMAC:
Mid-screen:
312 xx db+1, ji1, f+22 xx db+1 [21%]
112 xx db+2 (3 hits~EX), dash, njp, f+223 xx db+1, f+3 xx db+1 [31%]
112 xx db+2 (3 hits~EX), run d+2, (f+22 xx) db+1, f+3 xx db+1 [31%/(33%)]
njp, (run) d+2, db+1, ji1, f+2 xx db+1 [24%]
air-to-air jp, f+224 xx db+1, f+3 xx db+1 [20%]
Corner:
312 xx db+1, ji1, 112 xx db+1 [26%]
112 xx EX bf+1, d+1, 112 xx db+1, f+3 xx db+1 [33%]
312 xx EX bf+1, 112 xx db+1, f+3 xx db+1 [35%]
112 xx EX bf+3, 22 xx db+1, f+3 xx db+1 [30%]
njp, ji3, 22 xx db+1, 22 xx db+1 [25%]
KOTAL KAHN:
Mid-screen:
312 xx db+1, 112 xx db+1 [30%]
112 xx db+2 (3 hits~EX), dash, njp, f+22 xx db+1, f+3 xx db+1 [33%]
112 xx db+2 (3 hits~EX), run d+2, f22 xx db+1, f+3 xx db+1 [35%]
njp, ji3, f+22 xx db+1, f+3 xx db+1 [26%]
air-to-air jp, f+22 xx db+1, f+3 xx db+1 [26%]
Corner:
f+223 xx db+1, 112 xx db+1 [26%]
112 xx EX bf+1, d+1, 112 xx db+1, f+3 xx db+1 [37%]
312 xx EX bf+1, 112 xx db+1, f+3 xx db+1 [39%]
112 xx EX bf+3, 22 xx db+1, f+3 xx db+1 [34%]
njp, ji3, 1, 112 xx db+1, f+3 xx db+1 [29%]
SUB-ZERO:
Mid-screen:
112 xx db+1, teleport njp, f+22 xx db+1 [21%]
112 xx db+1, jip, 112 xx db+2 (3 hits~EX), dash, njp, f+22 xx db+1 [29%]
112 xx db+2 (1 hit~EX), f+3 xx db+1, teleport njp, f+3 xx db1 [24%]
112 xx db+2 (2 hits~EX), db+1, 112 xx db+1 [23%]
112 xx db+2 (2 hits~EX), db+1, teleport njp, f+3 xx db+1 [23%]
njp, f+3 xx db+1, 22 xx db+1 [16%]
air-to-air jp, f+22 xx db+2 (1 hit~EX), db+1, teleport njp, f+3 xx db+1 [21%]
Corner:
112 xx db+1, teleport njp, ji1, ji3, 112 xx db+1 [23%]
112 xx db+1, jip, 312 xx EX bf+1, d+1, d+1, 112 xx db+1 [31%]
112 xx EX bf+3, 1 xx db+1, teleport njp, f+3 xx db+1 [27%]
njp, ji3, 1 xx db+1, f+3 xx db+1 [17%]
MILEENA:
Mid-screen:
112 xx db+1, njp, ji3, f+22 xx db+1 [26%]
112 xx db+2 (3 hits~EX), dash, njp, f+22 xx db+1, f+3 xx db+1 [31%]
njp, ji3, f+22 xx db+1, 22 xx db+1 [24%]
air-to-air jp, f+2 xx db+1, njp, f+3 xx db+1 [20%]
Corner:
112 xx db+1, walk under d+2, 112 xx db+1 [29%]
f+223 xx db+1, walk under d+2, 112 xx db+1 [27%]
112 xx EX bf+1, db+1, walk under d+2, 112 xx db+1 [36%]
312 xx EX bf+1, db+1, walk under d+2, 112 xx db+1 [39%]
112 xx EX bf+3, f+3 xx db+1, walk under d+2, f+3 xx db+1 [35%]
njp, ji3, db+1, walk under d+2, 112 xx db+1 [28%]
TAKEDA:
Mid-screen:
db+1, f+22(4) xx db+1 [17%/(21%)]
112 xx db+2 (1 hit~EX), db+1~b, f+2 xx db+1 [25%]
njp, db+1~f, f+22 xx db+1 [21%]
Corner:
db+1, njp, ji1, ji3, 112 xx db+1 [29%]
112 xx db+2 (1 hit~EX), njp, db+1, 112 xx db+1 [30%]
njp, db+1~f, 1, 112 xx db+1 [24%]
JACQUI BRIGGS:
Mid-screen:
112 xx db+1, f+22 xx db+1 [19%]
312 xx db+1, f+22 xx db+1 [22%]
njp, db+1, 112 xx db+1 [18%] (kinda tricky but couldn't find another way)
Corner:
112 xx db+1, 1, 112 xx db+1 [23%]
312 xx db+1, 1, 112 xx db+1 [25%]
njp, db+1, ji1, ji3, 112 xx db+1 [22%]
REPTILE:
Corner:
112 xx db+2 (1 hit~EX), njp, db+1, 22 xx db+1 [27%]
njp, db+1, ji3, 112 xx db+1 [22%]
RAIDEN:
Mid-screen:
njp, (run) d+2, (f+22 xx) db+1 [23%/(26%)]
EX bf+3, db+1 [19%]
QUAN CHI:
Mid-screen:
312 xx db+1, teleport njp, ji3, f+22 xx db+1 [26%]
312 xx db+1, jip, 112 xx db+2 (3 hits~EX), f+22 xx db+1 [33%]
112 xx db+1, jip, 112 xx db+2 (3 hits~EX), dash, njp, f+22 xx db+1 [32%]
112 xx db+2 (3 hits~EX), dash, njp, f+22 xx db+1, ji1, 312 xx db+1 [32%]
njp, ji3, f+22 xx db+1, ji1, 312 xx db+1 [26%]
air-to-air jp, f+22(3) xx db+1, ji1, 312 xx db+1 [22%/(24%)]
Corner: (For the njp, walk forward until Quan Chi slows down a bit before jumping so he stays in the corner.)
112 xx db+1, njp, d+2, 112 xx db+1 [28%]
312 xx db+1, njp, d+2, 112 xx db+1 [30%]
112 xx EX bf+1, d+1, 112 xx db+1, njp, 22 xx db+1 [35%]
312 xx EX bf+1, 112 xx db+1, njp, 22 xx db+1 [37%]
112 xx EX bf+3, 22 xx db+1, njp, 22 xx db+1 [32%]
njp, ji1, ji3, 112 xx db+1, 312 xx db+1 [26%]