There are all sorts of forms of fiber and stool softeners that are NOT laxatives. Miralax isn't really a laxative if you take it in reasonable doses. None of those things get absorbed by the body, so they are recomended by GI docs.
Probiotics may help especially with the gas, and there are tons of those available. If you do a search in the box at the top of the page you can find loads of conversations that will give you some good ideas where to start.
You can look up non-gassy foods to help with the bloating too.
Some of the fibers will give you gas until you get used to them. I recommend reading lots of labels, looking up these things before you buy a bunch and decide some aren't for you.