Sony Nex F3, 5R or 6?

I got a Canon 5D MKI, and I bought my wife a Nex F3.

autofocus of the nex in low light / low contrast is not good.

So forget making photos of running kids indoors with autofocus. You should rely on manual focus  with focus peaking. Your choice if you like that or not.

The kit lens is ok, but not very fast. You may consider the sigma 30mm f/2.8. Cheap and good.

Raw image quality is great. I don't like its JPGs