I can't imagine many of the smaller cars mentioned here will make it to the US. Feel free to bash my opinions, but here they go:
I doubt either of the sport hatches will make it. FWD 1 series Gran Turismo - no way. City Compact - seriously doubt it, especially if there is the electic "i" in the works.
F.A.S.T. would compete with the Audi A3 and with AWD, the physical height and price will be higher, perhaps making it a NA possibility. Z2 also seems reasonable enough for NA market.
2 series coupes & verts will make it, although with this lineup proliferation, would it be surprising to see 1 engine only instead of the 2 engines choices now? I don't see how an M2 could have a turbo-ed 4 and leave room underneath for 2 smaller diplacement engines with enough difference in output to justify 2 engine choices.
I can't image the 2 series coupes & verts will be 6 cylinders unless the M2 is much lighter and turbo'ed out, thusly making it much faster. Even if this were the case, people would be very hesitant to pay more for a car with fewer cylinders, even if the output numbers are there.
M1 concept is hot air IMHO. BMW doesn't need to compete with Porsche, and they don't want to, thus the entry level of the Z2, the only small size 2 seater.