Hi Amar,
Nice work so far.
Since you are looking for some criticism, I would like to give you a brand of criticism called constructive criticism.
First off, I have attached a modified image (I hope) of two areas of your model that caught my attention.
1. The Head Mesh:
Overall it looks fine. Since I don't know what kind of athstetics that you are aiming for I won't offer many comments in that area.
I did spot a 3-point patch in the mesh near the front of the ear. The top portion of the attached image offers one possible way to solve that situation with 4-point patches and hooks it if you desire to remove it.
Also it looks as if you need to flip the normals of one of a 5-point patch in the ear itself. I pointed to that in the image as well.
2. The "Bottom Heavy Area":
Like you, I have no problem with "bottom heavy" areas and that is not a problem on this model.
I would say that there may be a problem with the model being "bottom high" at this point in the modeling process.
Here is what I mean:
If you look critically at the view of your figure's butt in relation to the torso you may find that it is not quite flowing with the rest of the body's contours.
The top of the woman's butt should flow into the small of her back and that transition should occur below her navel (maybe about 3/4 of the way up from her crotch... but of course you can use use your artistic license).
Now you did mention that you are working in that waist to hip area now so maybe you that is something that you have already addressed. In the image I attached I have made a crude representation of a possible alteration you can try with that.
3. The Costume:
Nice drawings by the way. They are all nice costumes.
If I had to pick only one I would pick the third one (the one with the shorts). The shape of the figure in that drawing also seems to be more in line with the figure you are modeling.
But if you have a script that you are working from the story could possibly help determine what kind of costume would work best for you.
Well I hope that helps you out some Amar.