Okay, I've got a few issue for you lovely ladies to help resolve today. 
#1
I've chosen 3 girls (possibly 4) to be bridesmaids at my wedding. My MOH is my closest friend, we do everything together, and she's also my FI's best friend. She's about 5' 10" and pretty fit, but you can still tell she's VERY tall (especially up against my tiny 5'5" 105lb frame).
Next in line is my life-long friend from elementary school, about 5'10", as well, slightly slimmer than the MOH.
Last in line is a close friend who is pretty much my personal psychiatrist; she's about 5'5" or so, but a very heavy girl with drastically different features from the other two.
I LOVE these girls, but the MOH and the last girl I mentioned don't really care for each other- only in my presence. I don't want to be rude by seeming to leave her out by choosing the dresses to fit the figures of the first 2. But, I've already chosen my dresses.

Do you think this will still flatter her figure? I'm trying to go with what my MOH and I like the most, and this is definitely what we both LOVE, but I don't want to make her wear a dress she won't look good in. I know the day's about me, but I still want her to feel comfortable rather than insecure, because I know she's pretty self conscious already.
My FI isn't the biggest fan of bridesmaid #3, either.
#2
Also, my FI is somewhat of a loner. He works on a ranch and does so by himself all day. So, he doesn't have the large social circle of friends that I do since I work in customer service, surrounded by people all day. His groomsmen will most likely consist of older men (40-50ish) and possibly his older brother (he's 21, at the moment).
Do you think it would be creepy if the men walked down the aisle with my young (18-19ish) bridesmaids? None of them really know each other (other than my dad, who is likely to be a groomsman as well as walk me down the aisle).
This is all pretty confusing. I'm sorry it's so long.
Thanks in advance for your help. 