I got a broken 2011 MBP for cheap and did that "conversion". You need the original motherboard for this and the keyboard and trackpad work as follows for me:
Long story short: It works in Windows (as "mouse" only, no gestures on the trackpad). In MacOS and Linux (tried Ubuntu) all gestures work out of the box as well. On Android_x86 it works if you connect it BEFORE booting Android (including gestures), if you plug it in after booting, the trackpad will not work.
On Android phones/tablets I can't get the trackpad working AT ALL (if anyone could help me I would be super grateful!)
Someone did it with a mid 2012 MBP (like a guy on hackaday) who described everything in greater detail: https://www.eevblog.com/forum/proje...rackpad-from-macbook-pro-(mid-2012)-trackpad/
If you also get a 2012 MBP that could be enough, if you get a different year model it's probably better to get the schematics online (somewhat easy to find on Google) like I did. In general (from looking at the schematics from all kinds of different models/years) this should be possible for MacBook Pro's from 2008 to 2016 (when they introduced the force trackpad I think). MacBook Pro's before 2008 (in the old design before unibody) it should also be possible and much easier and the controller is on the back of the trackpad itself. I can't find it right now, but Googling this should bring results. Hope this helps you.