One thing that worries me a bit is the one related to FF material, in kh3, especially that of secret bosses and summon .
Now here's what I think it would work in kh3
Secret Bosses
Sephiroth normal form + sephirtoh Safer form
ghilgamesh
Kefca
Caius ballad
Ardyn
Lightning
Noctis
Balthier +fran
Vaan +penelo
Ultros + thyphon
And as dlc the ff7 weapon ( diamand , runy, emerald, Sapphire, ultima , Jade , and omega )
Summon
The Gullwings ( the trio yuna , rikku and paine) as evolution of the summon Tinker Bell ,were Yuna will care for us, rikku will strengthen us, and paine will cause negative status to the enemies, and for the final attak they use Delta Attack
Nanaki as evolution of the summon simba which, in addition to carrying out a series of fire attacks, performs asfinal move the Infernal Flames attack.
The chocobo as a special summon to be used to move more quickly through the open world areas
Bahamuth from ffx , classic summon which also acts as a secret boss
http://sakuyamon.deviantart.com/art/Kingdom-Hearts-Summon-Bahamut-318752317
And as summons that I must first defeat : ifreeta, ramwel and shivalry from world of ff, since I think they have a personality perfectly to interact with sora
http://finalfantasy.wikia.com/wiki/File:WoFF_Ifreeta.png
http://finalfantasy.wikia.com/wiki/File:WoFF_Shivalry.png
http://rpgvaliant.com/world-final-fantasy-adds-rikku-ramuhs-granddaughter-gets-screenshots-shantotto
and as dlc
the trio mogle , tomberry and kyatus
http://finalfantasy.wikia.com/wiki/File:Mog_Tonberry_Cactuar_Art_T0.jpg
cat sith from ff7
What do you think of it? , Is there any chance of finding them in kh3?