Well made Unpotted pickups don’t squeal, only the bad ones do
I only use Unpotted humbuckers in all my guitars and have never had an issue in over 30 odd years
Potted pickups sound like shit
Get some T top replicas from a good winder or just get a set of Dr Vintage from Wolfetone. If you do decide to go the 57 Classics route just get 2 or them. Leave the 57 Classic+ out of the equation. Middle position tones will be much better
I have a 335 Studio with 57 Classics, and another with Burstbucker 1 & 2. I like both but give the edge to the Burstbuckers.
I just bought a set of Gibson MHS pickups that came out of a 335. Have not installed them yet but I've played a 335 with MHS and really liked it, so that may be another option.
I think T-tops would also be fantastic (I have them in a '76 LP Standard). You may be able to find a set of the modern T-tops used somewhere.