The obvious way to answer this question is to remove the pickguard of your own guitar and take a look.
The pickup cavities in the Squier Vintage Modified Telecaster Custom and Custom II were identical - generous enough to accept HB or P90, respectively, with just a change of pickguard. Your guitar could be the same.
Are you changing out the P90s to get hum cancellation or for reasons of tone?
Second part answer. High output pickups in semi-solid Thinline guitars are usually a short cut to howling feedback. I cannot honestly recommend anything hotter than a Brobucker.