The reason I'm asking is because I need tu upgrade my Lubuntu install (i'm running 18.04) and i tried 20.04 but i didn't like LXQt all that much, so if i installed Ubuntu minimal 20.04, and installed LXDE on that, would it be the same thing as Lubuntu 20.04 minus all the programs and with LXDE instead? I'm trying to keep my install as light as possible while still being easy ish to use.

Put more bluntly, would an install of ubuntu minimal plus all packages used by lubuntu (without removing anything) be the same as just using lubuntu?

Also, a side question: is there an alternative to LXDE/OpenBox that is equally as light and uses GTK instead of Qt? I don't think OB had an update in years. i don't really think that's too much of a problem though, but Itd be nice to know.