Contract law/Memorandum based on breach of contract

Bugs & Daffy are both actors.  They hear that Warmer Brothers (Warmer) is looking for actors to act in their new series of Goofy Toons short films.  Warmer finally puts the agreement into writing and hires Bugs and Daffy for a period of one year and $100,000 each.  Two months into the work for Warmer, Bugs and Daffy get fired from Warmer without cause.  Bugs and Daffy sue Warmer for breach of contract.  Bugs and Daffy submit the contract into evidence.  Bugs wants to orally testify that Warmer also additionally agreed that they (Bugs and Daffy) could keep any costumes they wore while filming for Warmer.  Just after filing their suit, Daffy gets an offer to work for Hanna-Barbara, a competitor of Warmer for $50,000, doing the same kind of work as Daffy was doing for Warmer.  Daffy decides not to because of his Warmer suit with Bugs.

You are a paralegal working for Judge Mel Blank who is the judge on the case.  The judge has asked you to draft a two-page memorandum on the rights and duties of Bugs and Daffy in this case.

Some links that may be helpful:

https://www.theguardian.com/money/work-blog/2013/aug/16/debunking-myths-employment-contract

http://www.rotlaw.com/legal-library/what-is-the-parol-evidence-rule/

https://www.youtube.com/watch?v=FxiyxWaM3kA