There "might" be "some" crossover between the two games, but not 100%. Some elements of Blood Moons will be unique to only Blood Moons.
We've talked about it, but no plans to add one.
It's done when it's done. Most likely will have another update or two before it goes stable.
No plans to change this at this time. The UI overhaul "might" have accommodations for such an update. Will have to see how that works out then.
As correctly answered by others, there have been vacations, events, and lots of bug fixing that have taken up our time the past few weeks.
He's been working on some good stuff, but I'll let him fill you in if and when he decides to respond.