First of all, I'm sorry for your loss.
Secondly, I'm fairly sure the stuff in your pic is just "junk." The buff Luke Skywalker figure is for sure junk....everyone and their brother bought about 6 of them back in 1995 hoping they'd strike it rich someday. Maybe that rubber Batman has some value cause it looks old. I'm just saying it probably has no monetary value, but surely the sentimental value it has to you makes it not just "junk." Maybe if you keep it, it'll remind you of your friend when you see it.
And finally, I saw your thread on the Nirvana backstage pass. Very cool. At first I didn't understand the design, but it's deodorant. Smells like teen spirit? I see it's in a plastic case, but can you tell what material it is? If it's just paper, it might be hard to prove the authenticity, but if it's a thin "canvasy" material (almost like an old iron-on sheet for T-shirts) and it had adhesive on the back, then it's easier to prove it's legitimate. I have a few from the 90s when I was lucky enough to get passes to some shows, but not as desirable as a Nirvana pass