I have been a fan of the youlookfab website and forum for a while now but haven't really gotten into posting much... but I just had to reply to your post!
First of all, you sound like a great mom:) I think it is wonderful that you are doing these subtle things for your daughter to give her the tools to look beautiful and feel confident about herself, and in such a way that it's not all about the weight gain (the sephora makeover, the new haircut). I also think it's super that you want to help her find jeans that are made to fit *her* body shape.
I am a little older than your daughter (27) but I can relate to what she is going through - I went through a similar awkward phase myself, also because of medication I had to take during my teen years for chronic health problems (I wonder if it was the same thing?)...
Like your daughter I am also petite and a pretty pear:) My goal in life was to be 5'5"... but I only made it to 5"3." I'm really only 115 lbs, but that's quite a lot more than I weighed in high school when I was sick. My waist is a size smaller than my hips, which are by no means huge - I just have a small but curvy hourglass shape on a small frame.
Unlike your daughter, my torso is proportionately longer than my legs. When I wear 2.5" heels my perfect pants inseam is 30-31"... do you know what her inseam is? (for the shoe height she would be wearing with her new jeans)
I am fairly new to the premium jeans world, but I do have to say I have found a brand and fit that works well for pear-shapes. The brand is Joe's Jeans and the fit is the Honey Fit. These jeans have a touch of stretch in them and are very fitted throughout, and I find that they make me look nice and slim and sleek. The reason they work well for pear-shapes is they are countoured slightly to have tad more room for the hips/booty (while still being very fitted - it's not like they are a men's baggy, relaxed fit or like "mom" jeans from the SNL skit). Also, the waist is cut a tad smaller (which eliminates the gaping in the waist I usually end up with in regular jeans).
The Honey jeans have a low rise (but not too low - they are cut lower in the front and a tad higher in the back so there's no peekaboo underwear effect) and they are bootcut, which is a great versatile style to start with and helps balance out the hips. They come in a variety of washes and some have different pocket designs. I prefer a solid dark wash and plain, unadorned pockets, but that's just me - your daughter might like something different. Here's a link to a website showing the collection:
http://www.revolveclothing.com.....8;sc=Honey
Of course, now that I have a pair of Honey bootcuts, I am salivating for a pair of slim straight/skinny jeans. I am going to have to write Joe's and ask them to please make a skinny jean for us Honey fit pretty pear gals!
BTW, Joe's Honey jeans only come in one length, which I believe is a 34" inseam. I think this is 2" longer than most regular length jeans, so even if your daughter has long legs for her height she may still need alterations. I have a pair that I had altered and they look good even though I had to have 4" chopped off the bottom.
If your daughter does need alterations and is concerned that the altered hems at the bottom will look "dorky" I would suggest having an experienced tailor "reattach the original hems" when shortening the jeans. It costs more ($20 vs $12 in my area) but may be worth it. If she doesn't have any objections to having the legs hemmed the regular way, I would just be sure to specify clearly to the tailor that you want them to use the same color thread and the same size stitching that was used on the original hems. I've been disappointed before when I've gotten jeans back that have gold stitching on all the seams and had gold stitching on the original hems, but the tailor used BLUE thread on the altered hems (to match to color of the denim, I guess)... anyway, it just didn't look right! That's what I meant by "dorky" above.
Good luck shopping! I would be very interested in hearing how things work out, so keep us posted. If you end up finding a different jeans brand/fit for your daughter, I would also be thrilled to know what it is, because I will probably want to give them a try for myself!