Can you give us an example of that? I have only noticed a slight increase in RAM usage. For the most part it seems the same.
They are not a requirement, it is your system after all. We only ship 1 snap, Firefox, and there are many different alternatives available. I explained the Firefox snap here along with the reasoning why we switched. It is not a hard set requirement that we continue to use that but for now it is what we have decided on. If we do make a change it has to be something we can support with our small team.
I think you have done a good job at making your Lubuntu installation quite lean. I only have 2 other things that I would add as possibilities.
1.) You can disable qlipper if you don’t need a clipboard manager. Cut and paste operations will continue to function, you just won’t be able to look back through the previous clipboard items.
2.) You can disable the print applet if you don’t plan to do any printing.
Both of those things can be disabled in the LXQt session settings.