[Q] Touchwiz -> cyagenmod -> google edition topic

I have the S4 9505i Samsung edition with touchwiz, which I rooted and installed cyagenmod 11.
It was working fine, but now it's time to move on,
I'd like give my phone to my father but before doing it I would like to unroot and convert it to google play edition, so he can get Lollipop, OTA etc.

Questions:
- is it possible to flush stock google rom on a "touchwiz" edition? ( if I'm not mistakken at leas the partions sizes are different )
-is it possible to do it on a mac (which doesn't have odin) ?

Thanks