These are some excellent questions! I think that you'll be thrilled to hear that XMR is in the works! We do not have an estimated date for its release, but we'll be sure to make a big announcement here once we have moved forward with it.
Doge we actually used to support but removed support in version 1.34.1. As much as I would personally love to see the Shibes back in Exodus, there were some issues that we had encountered leading to us delisting it. Our official announcement can ber read here:
BlackCoin & ByteCoin are not on our radar at the moment, but I'd be more than happy to add them to our list of asset requests for you!