Sure! Here's the requested content in spun format with synonyms:
Cara is crazy about Fred and also Foster.
Cara has strong feelings for Fred, and also Felix.
Phineas holds a special place in the heart of Cara, and Felix.
Candy being with
Phineas and Felix.
Fred Candy, and Ferb.
Cathy is emotionally attached to both Fred and Foster.
I hope you find these variations helpful!