Hm....

Unsure. I guess I can allow it since there is no particular rule against it. So, go ahead and make a sheet using the host for a single person, and I'll have a look. What I think I'll do is make your special GM trait/flaw based around the fact that you are a single person host.

I warn you though, that single person obviously should be a highly skilled hero, otherwise you are probably going to die quickly.