Yeah, a lone striker doesn't have to be a big man. He just has to do whatever is needed from him (obvious). Not sure exactly what we would want from a lone striker in a 4-3-3 consisting of our current squad plus the rumored players (aside from goals ofc).
Assume we'd just go for someone who is very mobile and capable of both dropping off to link up with the wide players, but equally good at moving into the channels and getting behind the opposition defence. Again, not sure on the balance between those two because it all depends on the type of football we play.