This would be much better served by a different manufacturer methinks.
ePBT reverse dyesub still has yet to prove itself and the leadtimes are very long, plus they've closed off new orders as of this moment. But it looks like you've got a lot of work to do still and plenty of time before this is a viable set so maybe it'll work out.
Things to consider: 3 or 4 key 40's and Alice support in base if GMK because 40's kits are generally too pricey and minibars can pull double duty between Alice and 40's. Maybe a full 40's kit will work for ePBT though.
I can't foresee the support being there for a R0/R5 base kit.