"Also one keep in mind the with these very very large impactors they can throw into orbit or escape a large percentage of their mass- especial with smaller planets."

Ha! I reminded myself of something.

Why does the Moon need one impactor to be formed?

Couldn't the Moon be formed from a series of smaller impacts- say 1/2 dozen 160 km size impactor occuring over say, 50 million year period?

Additionally could the orbital cloud created make Earth a larger target and thereby increase the chance of near miss actually hitting earth?

And Earth high density could be by having it's surface *pecked away* by smaller impactor- anything in range of 50 Km in diameter and up.

Put it this way if a 50 km impactor hit Earth today with the Moon further than it was back then, wouldn't a fair amount the material ejected end up on the Moon? [also would this stuff affect the Moon's orbit?]

Also where most the material ends up from an impactor could affect the orbital distance from Earth. If material is mostly closer it can bring the Moon closer and if further away cause the Moon to move further away.
This can explain way Venus has no moon. It could throw it's moons out of orbit or cause them to spiral in to the Planet