Hm. Well, Yuna, when you bought up the topic of summonable Heartless enemies, I thought about these bosses that could summon heartless:
Miss Piggy- Aerial Knockers and Aerial Champs
Gonzo and Camilla- Cannon Gun, Silent Launcher, Ice Cannon, Switch launcher, and Jumbo cannons
Animal- CymbalMonkeys, Tricky Monkeys, Crescendos, Flare Notes, and Bubble Beats
Lew Zealand- Sea Neon, Screwdiver, Missile Diver, Aquatank, and Jet Balloon
Crazy Harry- Crimson Jazz, like you said, and Minute Bomb, Skater Bomb, Storm Bomb, and Detonator
The Swedish Chef- Aquatank, Black Fungus, Bulky Vendor, and maybe world exclusive Heartless like: Muppet Tomato Heartless, Muppet Cake Heartless, etc.
Marvin Suggs- red Nocturne, Blue Rhapsody, yellow Opera, Green Requiem, Black Ballade, Silver Rock, Emerald Blues, Crimson Jazz, Spring Metal, Scarlet Tango, Grey Caprese, Striped Aria, Sapphire Elegy, Pink Concerto, Turqouise March, Emerald Serenade, and world exclusive Heartless include: Muppaphone Heartless, Possessed Mallets
Sam the Eagle - Book Master, Runemaster, Barrier Master, and world exclusives include: Patriotic Heartless, Eagle Heartless
Link and Strangepork- They fly on the Swine Trek, you have to jump on board after shooting it down with spells, then you fight them and World Exclusives: Koozebanian Heartless