Any idea how water levels usually are in late may?

Usually, water levels in May will be fine, but you never know. There's not much of a snow pack and it could be a dry spring...who knows? The number of beaver dams is going to probably be a bigger factor anyway.

Note that a permit for EP 8 is for Moose River south. Rules don't allow you to go north and reenter the BWCA. Now if you like paddling small rivers that get little use, you could paddle up to the Echo Trail, but then you wouldn't even need a permit because that isn't in the BWCA.

I was wondering that too....the EP is for heading south
and the question is for going north?

cyclones30: "I was wondering that too....the EP is for heading south
and the question is for going north? "

I had the same question. I assume the OP intended to say EP 16. In any event the river level will be the same on either side of the EP.