1-Can i make the active limbs thinner without risking a permanent bend or breaking?
First, a lot of new guys get this misconception that a thin bow is going to break, or even that some thickness resists set. This is backward! You MUST make limbs thinner to avoid set (permanent bend) and the thinner a limb is, the less likely it is to break. BUT!!!!!!! A very thin limb like this IS at risk. NOT because it is thin, but because it is UNEVEN in either thickness or strain.
Right now you are worried that if you pull it more it will break. It probably would, but not because it is thin. The real reason is that some places are too thick, and others are thinner. So, the bend will find the thin places. They will bend too much, too far and could break there.
The solution is to watch that video about the gizmo. Do not pull the bow any farther yet, keep using the same 11 lb weight on the string and make the curve better. More even. Already we can see some places bending and some places not at all. Slowly scrape away wood where it isn't bending and you want it to bend.
2-Or can i narrow them (but i have rawhide on the side)?
Yes, you can narrow, but you will still need to fix thickness in some places. You can also taper the active limbs side to side if you want. There is no rule against it. The sides don't have to be parallel. maybe by thhe handle you leave it 2" wide like you have and maybe at the shoulders 1-1/2" wide. Then work on the bend again. Slowly.
3-Is the rawhide on the side necessary or can i remove it to show the wood?
Since the rawhide is on now, leave it on. Once the bend is better, you should work down the levers, too. They are too thick and heavy, more than you need.
