"For instance, loose skin, saggy breasts and Hair loss. Has anyone ever experienced any of these and if so, how did you deal with it? Is there anyway at all to prevent these things from happening?"
Hair loss - happens as your body reacts to the extreme quick weight loss. It goes on for a couple of months and then it stops and your hair comes back. I don't know anyone who has avoided it. It's temporary.
You don't say if you have kids, but if you do, your boobs already sag. Will this make them sag more? Yep. Any way to avoid it. Stay fat. But if you are going to have surgery, nope.
As for loose skin, that depends on many things - age, ethnicity, skin condition, amount of weight loss. I have some flab flapping around, but I lost 150 pounds. I wear those flaps like a badge of honor. I haven't had plastics. I'm about 3 years out from surgery and the mother of a 19 year old and a 16 year old. My boobs would have been sagging anyway because - GRAVITY. So, you don't need to go under the knife again. Get your head in the right place about why you are losing your weight. Adopt the plan early and exercise to the extent you can now.
Best of luck.