Fitting WRX 4 pot on the rear?

[Wolfy]

Good afternoon all,

So I decided to change the brake fluid yesterday, and well, It did not go to plan... I ended up snapping my rear inner Brembo nipple, as well rounding off the outer one, bearing in mind I gave them both a good torch and a blast of WD40. Thankfully, the rest loosened all ok. The pedal, however, does not feel safe at all. 

With that said, I had the Mrs assist with the brake pumping... Turned out she was doing it all wrong, and by this point, It was too dark to start over, so I called it a day. I'm not free to work on the car again until next weekend, so I'm yet to see if bleeding only 3 calipers will suffice until I figure out what to do. Drilling the nipple is an option, but from what I've heard, it's 50/50. The other option would be to buy another set of Brembos, but people on eBay are wanting stupid money.

Whilst moving the car though, I noticed I now have this strange creaking noise from the front right Brembo when I apply the brake. I'm not too sure how to properly describe it, but it sounds similar to over tightening a piece of wood in a vice. Any ideas?

Anyway, this is getting a bit of a long winded read, would it be possible to fit WRX 4 pot calipers onto the rear?