Hmm, maybe the benoni would be better paired with the Reti gambit? At least you'd be pretty comfortable when black pushes d4.
At a glance I'd say Benoni is not very principled, and Catalan is overly-principled (in the sense it'd take a high level positional player to squeeze out an advantage).
Would it carry you far... sure, even strong GMs will play the benoni sometimes... I don't think many would recommend it though.
1.d4 + 2.c4 will give you massive variety... the down side being that there is... massive variety
Against 1.d4 I might recommend the QGD for a year or two then add in the Nimzo. Those pair well and lead to a variety of games.
Against 1.e4 I think 1.e5 is very good, but obviously lots of openings can be recommended for various reasons.
I am a beginner that hopes to stick with my chosen opening forever so that I can master them. I want them to complement each other and add variety to my play. I don't just want to learn only openings that focus on one principle, like structure or attack potential, but an assortment of principles so I can effectively become a good chess player. I want to learn the Petrov against e4, Benoni against d4, and the Catalan as white. Do you think these openings are absurd for a beginner to learn? Are they able to carry me to a high elo or will I have to pick up more openings? Also, I know as a beginner to chess I should focus on endgames and middlegames (which I am!) but openings are just so interesting to me.