First off, good for you, losing all the weight. I have had a few clients that have had bypass. Some of them have struggled to eat enough to get ripped, but it can be done. I imagine you have a good amount of loose skin and for sure, a good amount can tighten up. Ive seen a client drop from 300 lbs to 200 lbs while gaining 10 lbs of muscle, over a year period of time and a lot of his skin tightened back. He was about 30 at the time. Still, there was some that did not.  There are factors here that will help determine if it will all go away or not. The amount of time you were big is one factor. The longer you were fat, the harder it will be to lose it. Another factor is age. The younger someone is, the better result they ususally get. So age is not on your side here. One reason age is a factor is becuase of growth hormone. GH is highly responsible for the elasticity of our skin. So GH would be my first suggestion. I would start with about 2iu a day. This will help with fat loss some and possibly help with your skin more than the result you would see otherwise. You can run this long term. The longer the better. 

As for steroids, the first thing I would do is get this HRT plan in order. It might take awhile. He will want to test your levels, possibly often, when you first start. So taking another steroid would throw off the results. I would amke sure that everything is right with HRT before starting other steroids. But the GH will be fine. That has no impact on test levels. When you are ready to ramp it up, you could incrrease the test to 500mg EW for 10 wks, then take equal period off. When you want to blast again, get your labs done to make sure everything is healthy. After you do a blast like this, if you want to up things for the next round, you could do a 12-16 wk blast with EQ. This is a great one for muscle gains. 400mg would be good, along with 500mg test.