I really do have to agree with Digizel - if nothing else, I don't think you need Chaosgallantmon and Megidramon/Crimson Mode and MedievelGallantmon. If there can be more, the ideas on how to treat the dark Megas also seem very sound and add validity to the fact that Guilmon's instability is a very bad thing.

(Though not sure about her being the strongest. Not sure when Omnimon and Alphamon will show up after all, unless Chaosgallantmon appears before Gallantmon)