I'd advocate against cameos of canonical characters, but even more I'd say not to include any more than three universes, and even then make sure that those are well-tied together.  The makers of DMC and Bayonetta have indicated that they take place in the same universe, and Darksiders aligns pretty closely.  All of them would be able to be a fully integrated universe, no multiverse necessary.

[quote=@EnterTheHero]
I could at least provide info on Bayonetta. I was pretty big on reading the codexes or whatever.
[/quote]

Superb.  You for Bayonetta, Sho for DMC, and me for Darksiders sounds good.