For sure, I play all sorts of things. Lately I'd say my time outside of Halo has been largely spent on CoD/WZ, Fortnite, Avengers, THPS1&2, and I've recently gotten hooked on Hades. Pretty excited for Star Wars Squadrons!
I'm not aware of any talks yet regarding any crossovers between Halo and Zenimax properties but internally I know a lot of folks would love to see something at some point. Considering some of the past crossovers with Sea of Thieves, Minecraft, and Forza, I assume something will eventually materialize but no idea what/where/when.
Re: Mod support for MCC - more robust mod support is definitely on the team's list and something they've always had ambitions around but for now I believe that work is all a bit further out, once H4 is out the door and some of these other pending features are released.
And I'm not able to talk about Infinite right now.