WITH REGARDS TO THE BEARD ISSUE
I think the reason why Cas has a beard and Dean doesn’t (Dean’s femininity aside), is because time passes differently for Castiel in Purgatory.
We’ve established that there is no notion of time in Purgatory, right?
Okay, so what if when Dean says “I prayed to you, Cas. Every night.”, that’s actually an understatement? Because Dean prays as much as he can.
What if Cas uses Dean’s prayers to mark the days?
And Dean’s prayers become more and more frequent as “time passes”
So Cas has had more days than Dean has.
And his body responds to this “notion”
Hence the beard