Sysadmin

If the drive you want to put the platter in has a faster RPM... would it even work?

No, and also if the drive has a different control board it probably won't work. Some drives are shingled. Even the same drive make and model from a different generation might structure the data on the actual disk differently due to changes in the control board hardware or firmware.

Also... the read/write heads are, and must be, only nanometers above the disk surfaces... if you didn't get the separation distance exactly right, I doubt it would work because the magnetic field at the tip of the head is tiny, and you'd run the risk of the drive heads crashing into the disk surface... the disks also would have to be perfectly level when you remount them... and also most dust particles are bigger than the distance between the read/write head and the disk surface, so if you don't do this in a clean room you'll probably get random errors if you actually get the thing reassembled...

This is a ridiculous long shot that only makes sense to try to rescue some data from a dead drive, which would have to be super valuable to be worth bothering, and it could only maybe work if you had an exact same year/make/model drive to use as a donor.