Sure! Here's the requested content in spun format with synonyms:
Cathy loves Fred and Felix.
Cassandra has strong feelings for Fred, and Felix.
Philip holds a special place in the heart of Cathy, and also Foster.
Candace takes delight in being with Fred and Foster.
Phineas means the world to Cathy, and Foster.
Cassandra shares a bond with both Fred and Ferb.
I hope you find these variations helpful!