Re: I have narrowed it down to two bikes VOTE FOR THE ONE U THINK I SHULD GET!
i'd go with the firestone. for one, it's not a girly bike. by that, i mean, since it has the top tube, it's a LOT more stable. i've restored vintage girl's bikes before, and they're really shakey. that's without motors. i rode one down a big hill and thought it was gonna break in half. and since you're young, you're probably gonna be beating on it. i know i did, when i was a kid. i mean, i still thrash on my bikes. i jump speed bumps all the time at 30mph...
also, that firestone bike is a middleweight. that means it's not as heavy duty as a "balloon tire, heavyweight." the wheels are skinnier, and the spokes are weaker. and since it's 50 years old, you're gonna have to upgrade them.
AND, the forks are bent. look closely at the pictures. they shouldn't be raked backwards from the headtube of the frame.
i'd keep looking.
by the way, you're 11, right? how tall are you? you might be able to find a cool 24" cruiser. the frames usually aren't much smaller, so you could still squeeze a motor in there.
some of those old cruisers are pretty big and sit kinda tall.
if i find anything, i'll let you know.