Are all f type wheels interchangeable
I have a heated round one bit being tall I would like a flat bottomed one mine is a 2018

 

I think so.
I had my original round one with heating replaced by an OEM flat-bottomed one also with heating a few weeks ago without any problems.

 

Mostly yes. Earlier models had a slightly different alignment marks on the inside of the steering wheel as well as the controls on the steering wheel not being compatible with later model years. So if you stay clear of a donor wheel from 2014-early 2015, you should be fine. Technically the design has not changed, so you could transplant over your fascia and controls/wire harness if you wanted too. Everything else (like paddle shifters) should work the same.