I would guess, yes. Please be patient, because the server, Empires, is new. And it takes a little tiny bit to get everything set-up. But do be patient, because empires, will be evolved soon to be something big, a major attraction to Minetime! In the mean time, just be patient and you should try out Minetime's other servers! We have many perks available on them!
They won't be added. Empires is seperate from Minetime, people who own an empire make their own donator perks.
Empires takes a lot to hold itself up every month. It's for that reason that Empires are monthly subscriptions instead of payments, and it's also for that reason that donor perks will probably not be added (as they would only have to pay once, and that would be hard to sustain the whole that is Empires).
If you want more slots/plugins upgrade your empire As you noticed no donators have their ranks in empire because there is no point to them.