Earlier quoted context omitted.
You would just learn Egyptian or Lebanese arabic, everyone would understand you. Written (formal) arabic is a different story though, I think that's what's commonly taught for non arabic people
I would add Syrian to that list. But even within these dialects, there are regional dialects that might be difficult to understand even for native speakers from that same country. For example, Tunisian Arabic can (roughly) be divided into northern and southern dialects. I've met people in the north who think I'm from Libya because of some words that are shared with southern Tunisian Arabic. Tunisia is a relatively sm…
But note that Egyptian Arabic is very different from Lebanese and Syrian Arabic (which both are in the Levantine Arabic family).