Post-pregnancy stomach

So as a little background: I weighed about 130 before I got pregnant with my son. For my own (unfortunate) personal reasons, I was up to 247 by the end of my pregnancy. It's taken me about 3 years of not really doing anything for my metabolism to shed all the extra weight... and now, I'm sick of feeling fatigued after eating once a night (before bed), a single meal consisting of pizza, pizza rolls, burritos, or whatever other nonsense I had readily available the was 'easy' for me to make and eat before sleep.
I've always had issues with my appetite--generally, I have to force myself to eat when I should...
Roughly a year ago, I swapped out all my sodas and juices and constant chocolate milk binging for a more subtle drink--water with crystal light packets added for flavor. Aside from Tuesday nights (when I allow myself to enjoy a kiddy-cocktail or two at my bar--no alcohol for me), it's literally all I drink. However, since having my gall bladder removed about 5 years ago, I have never been able to drink a lot of... anything, really. I average about 40 oz a day. Still, better than 40 oz of soda.
About 3 weeks ago, I opted to start eating right and exercising a little more (versus the literally 'nothing' I was at). In the first week and an half, I lost 7 lbs. I'm assuming mostly water weight, but this 'healthy' thing is new to me--I've always let my metabolism work out the 'kinks' in my figure... up until the loss of my gall bladder, at which point, I never really put on any weight anyways. After that initial drop in weight, I've lost another 2 lbs since--which seems right to me, especially since my workouts HAVE resulted in a slight muscle gain, though nothing too significant.
So here's my first question--and this goes out to all the mothers out there that have struggled to shed that post-pregnancy belly:
I don't have loose, sagging skin, and so far, my skin has retained a decent shape around my abdomen... but I DID have a c-section, and I was wondering this--will the elasticity of my skin allow for a 'tighter' look after I lose weight, or will it become saggy? And will I always retain a slight 'muff-top' appearance due to the c-section... despite any sort of weight loss?
My questions for anyone else out there:
I understand that it's 'good' to exercise AND diet at the same time... but ultimately, which do you find personally produces better results?
As long as I'm sticking to 1200 calories a day, what would (hypothetically, as I AM eating 'good' foods) happen if I filled those calories with things like hamburger meat and excessive carbohydrates? Would I still lose weight, or would it stall since there are no real nutrients being consumed?
How much do things like fiber pills and fish oil really aid in weight loss and being healthy? And are there any multivitamins out there that you find help boost your body?--not necessarily to lose weight, but to genuinely help your body receive the 'fuel' it needs?
And finally, what is the best way you've found to cycle different exercises to benefit your body/muscle building without 'tearing up' one particular group of muscles? ei: do you do two days of strength training (and what type: body resistance, or actual weights) and then a day of cardio (again type: running, jump rope, jumping jacks, etc)...
You don't need to answer all of this. I've jam-packed a lot in here versus making individual posts for each question. lol
But any insight you can give me would be greatly appreciated.
Thanks.

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