Hi all, i'm working on a singlespeed conversion of an old girl's mountain bike, 24" wheels. i'm looking at 24" wheels to buy (it doesn't have any) and i'm trying to go as cheap as possible.

However, I see that almost all the rear wheels available say something like "6/7 spd FW hub" which I interpret as being ready to accept a multi-speed cassette. However, is this kind of hub also OK to screw on a bmx-type freewheel? Does it already come with an acceptable freewheel? Or do I need to specifically get a rear wheel made for singlespeed?

here's some examples of what i'm looking at: