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