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