Not sure how they enforce the rules now (or whether we even played by what would be considered "real" flag football rules), but when we played, it was kind of like trying to take a charge. So in pass protection, you could move your feet as long as you kept your hands at your side and kept giving ground. Penalties were called basically like on defense in basketball except for absolutely zero tolerance for anything that looked like hand checking.
So if that's the way they are doing it, you probably want a shifty wide receiver/CB type for center. If you literally are just setting a pick, maybe that makes a TE useful as the extra size makes it hard to get around.
