Is this even constitutionally feasible? Would the federal district be restricted to just the federal buildings, and if so, would it still get electoral votes?
Yes, the plan is that the federal district would be reduced to an area around the main government buildings, to be called "The Capital". Without a constitutional amendment, it'd still get electoral votes, but I understood the plan was to start the process of repealing the 23rd amendment to remove them. (If that didn't happen, how would the electors even be chosen?)
Anyway, the status quo is clearly unacceptable on basic democratic principles and Maryland doesn't want it back, so yes it should have statehood. I guess you could argue for it retaining some sort of special non-state status but being given proper representation in Congress via a constitutional amendment, like the Australian Capital Territory, but it'd be easier to get statehood through than that.