i haven't taken the time to read through all of this, but just some tidbits from me:
I am the shortest on my team at roughly 4' 11". we have girls in a range from my height to about 5' 4". As far as the weight thing, personally I don't like it, because frankly, as easy as it is to toss "smaller" (all relative) girls, its not always about the size. I am a very little girl, but its not my size that makes me skilled at coed stunting. its 1. my jump 2. my body awareness. i've seen girls that are close to 5' 6" stunt and be awesome at it, why? because they had an AWESOME jump and once they were up there they knew how to hold themselves. on the contrary, we had a girl tryout this past year who was itty bitty, about 4' 9" and skinny as a rail, and she was god awful. the guys were struggling to toss her just to hands, why? she didn't jump for crap.
i suppose making flyers maintain a certain weight is acceptable when done properly. giving the same weight to every girl is absurd, stupid, dangerous, i could go on. we are all built differently. they should each have their own personal target weight, and a healthy one at that. its not safe for a flyer, or any cheerleader for that matter, to be all skin and bones. its just not. thats how injuries happened. you need to be strengthening and conditioning and engaging muscles to have proper technique and to prevent injury, and if your weight is so low that you have no muscle to do so? bad news bears. not to mention all the psychological problems and eating disorders that could arise.
the topic of coed girls is very.... tricky? thats not the word i'm looking for. but pretty much its a balancing act, you really have to watch boundaries and take all factors into account when it comes to size.
sorry, i'll get off my soap box :)