Alright, got the go-ahead to write about double, so here's everything I remember. Just a note, if I put a * next to something, that means I'm not 100% and it needs to be re-checked. Also, when I say she "transforms into ____" I mean that she performs that same move as that characters does with the same button press.
s.lp: transforms into Filia, does her s.lp.
s.mp: transforms into Peacock, does her s.mp.
s.hp: transforms into Cerebella, does her Titan Knuckle f+hp.
s.lk: transforms into Valentine, does her s.lk.
s.mk: transforms into Parasoul, does her s.mk. ---> chains into s.mk: transforms into filia.
s.hk: transform into Ms. Fortune.
cr.lp: transforms into Filia.
cr.mp: transforms into Cerebella.
cr.hp: transforms into Filia.
cr.lk: transforms into Painwheel.
cr.mk: transforms into Parasoul.
cr.hk: I don't remember. jmcrofts on SRK says it's Valentine's cr.hk.
j.lp: transforms into Ms. Fortune.
j.mp: transforms into Filia.
j.hp: transforms into Painwheel.*
j.lk: transforms into Parasoul*
j.mk: transforms into Valentine.
j.hk: transforms into Peacock.
236lp: transforms into Parasoul, fires a shot directly ahead of her. Misses most/all characters crouching.
236mp: transforms into Parasoul, fires a shot diagonally downward. Can OTG.
236hp: transforms into Parasoul, fires a shot at the ground that bounces up. Good amount of hit-stun on airborne characters. Can follow up with an OTG combo.
623K: transforms into Cerebella and does a "butt-slam". Invincible on start up, can OTG combo after the HK version.
j.214lk: transforms into a teacup. Causes stagger on standing opponents, very little hit stun on air borne opponents. Hits mid.
j.214mk: transforms into a barrel. Knocks opponents down, can OTG after wards. Hits mid.
j.214hk: transforms into a refrigerator. Causes a ground bounce on air borne opponents. Hits mid.
B+lk+hk: transforms into Filia and slides along the ground. Small bounce on hit, can OTG. If used against a standing opponent, can OTG combo after.
236pp: Transforms into a car, full projectile invincibility. Don't know if it's fully invincible, or just projectile.
236kk: summons a number of ms. fortune heads. Does good chip, you gain 1/3 meter while in this state. Light attacks have the heads attack forwards, medium causes them to go up-forward, heavy makes them go downward, if they're already in the air.
214pp: Her level 3 attack. A very short rushing attack. When it lands, a canned animation starts where the opponent is bounced around the screen. If an outside factor (like fortune heads) causes a hit to miss, the animation immediately ends.
214kk: Level 5. transforms into one of the Easter Island heads from Gradius. Tapping on a punch button while in this mode fires off rings that hit multiple times, and forces standing. The rings do the lowest damage. lk/mk* summons box car george, knocks opponents up into the air. hk summons 3 airplane bombs in a vague gradius formation. Knocks down on hit. Also does the best damage.
This combo is confirmed to work against Cerebella in the corner. It's likely it won't work on some of the lighter characters.
s.lk > s.mk > s.mk > s.hk xx 236hp > s.lp > s.mp > s.mk > s.mk > s.hk > jc > j.mp > j.hp > (land) > cr.mp > s.hk > jc > j.lk > j.mk xx 214hk > (land) xx 236kk > st.hp.
The benefit of this combo is that it summons fortune heads and causes slide, which I believe the opponent can't tech roll from.
I also know it's possible to combo into Double's j.hk, cancel into barrel and link st.lp after, however I don't know the annotation for it.
Damn SRK grammar Nazi's.