Use the Google Search feature of the search, it does a better job.
Used machine screw and nut with the white snap caps on the exposed head outside the closet. Snap caps available from scamp
store used to cover rivets. Work fine with #8 machine screws, maybe even #10. This is what some folks do to replace all the rivets. I put my curtain rod brackets in this way with #8 stainless screws and brass hex nuts to match the brackets.
Poles that go top to bottom with wire shelves attached.
The 3M 4200 mentioned is a marine adhesive caulk with an excellent reputation.
Epoxy with various brands used, but there is some minor disagreement on using epoxy with FG. (Epoxy a potential search term)
3M makes a tape that people have used to attach solar
panels and awning
tracks with. Supposed to be pretty good.
fiberglass blocks of wood to wall (it's how the scamp
front bunk wood mount is attached to wall. Generally called "tabbing" it's essentially using fiberglass cloth and resin like a tape.
Depending on the load you plan to put on shelves you could probably use rivets with snap caps from the outside into the wood. Drill a tight fitting hole through closet side into wood, when the rivet expands it will grip the wood.
Ikea shelving (as a search term) different folks have put shelving in from Ikea using different methods of attachement.