Here's the roster of FF characters(they all counts as Kingdom Hearts characters, even when some of them doesn't appeared in any official Kingdom hearts games so far) that's shows up in Ani-toonspiracy(sorted by FF they comes from):

FF1:

• Warriors of Light(summon character)

FF2:

• Firion
• Minhu

FF3:

• Moogles(this was nothing new in KIngdom Hearts)

FF4:

• Rydia

FF5:

• Barts Kaluser
• Faris Schwertz

FF6:

• Locke Cole
• Setzer Gabbiani
• Terra Branford
• Sabin Rene Figaro
• Edgar Roni Figaro(he's Cid Highwind's cellmate)

FF7:

• Cloud Strife
• Tifa Lockhart
• Barrett Wallace
• Aerith Gainsborough
• Red XIII
• Yuffie Kisaragi
• Vincent Valentine
• Cait Sith
• Cid Highwind
• Zack Fair

FF8:

• Squall Leonheart
• Rinoa Hearthily
• Selphie TImmitt
• Seifer Almassy
• Fuu
• Rai

FF9:

• Vivi Ornitier
• Zidane Tribal
• Princess Garnet
• Steiner

FF10:

• Tidus
• Wakka
• Auron
• Yuna
• Rikku
• Paine

FF1-5 characters here will be mostly their reincarnations or/and descendants