gibson burstbucker pickup

Could you replace a humbucker with a P-90 and vice versa?
Ok, I have 2 scenarios for you guys, so here it goes (answer both):
(1) I really do have a Squire Fat Strat (link http://www.squierguitars.com/products/se… so I want to replace the bridge pickup (which is an open-coil humbucker) with a Gibson P-90 or P-94 (link 1: http://www.gibson.com/en%2Dus/Divisions/… link 2: http://www.gibson.com/en%2Dus/Divisions/… Is that possible?
(2) Say I have an Epiphone Casino (which goes for $500 these days, btw) and I want to replace the bridge P-90 with a BurstBucker #1. Is that also possible?
btw, I know that the pickups on a Squire HSS sucks, but I don’t have the money to replace them all-yet. I don’t want a Strat for a guitar, I’m probably gonna upgrade to a Casino next and possibly do scenario 2.
HAHAHA and for any /b/tards out there, CP lol
sometimes they don’t fit just right, they are too tight or loose- loose is worse because you get pickups which slam around and make knocking noises. Then you have to find a way to make them secure and you end up with big empty areas around your pickups where sound bounces around and dirt collects and this defeats the purpose of changing them in the first place. If you have never done work on a guitar before I would take it to a luthier- one who specializes in the construction and repair of guitars and ask them if it is feasable.
Gibson Les Paul with Burstbucker 1 and 2