TBH, since you are doing a 'conversion' you should get your rear wheel 1st (get proper width!) and check your chainline... That way you can see if your chainline is OK before you dump loads of cash into cranks that you might not need.... The last conversion that I did used the same chainwheels and cranks, but just needed a little narrower BB. For some reason it used to be a road-double, but it had a road-triple (aka MTB) BB... weird. Anyway, it's fixed now! (53/17x700c... big chainring!)

I like the flip-flop hubs too, you can usually run them with no dish in the rear, so it makes for a very strong wheel that is super easy to work on.