The red dot you listed isn’t indestructible, no sight is (I get that it just a figure of speech, but just clarifying as some are more robust than others), but the Sig is a good budget option. It’s probably in the second tier of red dots out there (first tier being Aimpoints, Trijicons, etc.) and would serve you well for your purposes.
Regular AR sights regardless if it’s a pistol or a rifle. Again I’d look to a good set without breaking the bank; Magpul MBUS sights are probably the gold standard of quality and affordability here.Along with the RDS, I'm looking for flip up sights. I'm not sure about the sights needing to be elevated due to it being a pistol or what the deal is with that. Willing to spend 'around' $80 or so on this option.
It’s slightly above your budget, but the Streamlight ProTac rail is a good light (again without breaking the bank). It’s an older light, as they have newer lights with more output; which means you could likely find these on clearance somewhere. Do yourself a favor and don’t cheap out on the light, you really get what you pay for here. Additionally with the mount they use you can position the light where it’s out of your way and run the activation switch somewhere convenient.I am needing a light on this guy. Since it is fairly compact, i feel like there's no space for a light. My hand wraps around the top of the pistol for grip and I feel like the light might get in the way with handling the pistol. What light options are available if you had an AR pistol? Willing to spend less than $80.
Hope this gives you some options.