Missed this part of the question.
Crouse has an aaPPG of 22, so his upside is probably in the .4-.6 NHL PPG range. Maybe not a bad pick later in round 1, but definitely not Top 10 material. The fact that some ranking services have him over Strome or Marner is laughable.
Connor Brown and Brendan Leipsic would use different equivalency factors now since they're both in the AHL. I haven't really looked at the AHL/NHLE together much to be honest.
In their draft eligible seasons though, Connor Brown's was 17 and Brendan Leipsic's was 18. Which makes sense, since both were long shot prospects. I'm sure they've helped their stock with their AHL performances, but again, I've only really looked in depth at performance in a player's draft eligible season.