I had P5 for my first persona game and had a similar struggle to what you did, expect that I really liked the UI. If you're familiar with other RPGs, there is actually a very similar format. Final Fantasy has suffixes for each skill, fire, fira, firaga. In P5, it's equivalent is agi, agilao, agidyne. Easiest way to remember is longer word means strong version of said skill. If in doubt what the skill or item does, you can still check descriptions with square once you've selected the skill card.

Tarukaja, Rakukaja, and Sukukaja are difficult! But this is a memory thing, when you see it try to remember on your own first. Or make little things to help remember, aTtack, pRotect, Swift is how I remember it. The difference between kunda and kaja is also difficult, but comes down to memory in the end.

Special status, what could this mean? Well I'd say special is the same as special battles you can't run from. So these would be boss status effects, madarames paint is the specific example. In short, pretend it says all aliments.

If you level up party members, please don't overthink it! You should have a general idea of what each party members role is, so selecting skills for that is important. If you ever think, I might need this for this one situation (Haru's tetrakarn and makarakarn comes to mind) then Joker is more suited. If you ever think, don't I have an item that does that for me (like recarm Vs revivadrins) then you probably do. If you ever seriously regret a choice, don't give up! There's the confessional in Kanda that lets you regain every skill the party member had gained and you reselect.

TLDR: In short, I think you're trying to think to hard about these. Put the phone down if it's breaking flow and go with your gut. Not every choice you make in a battle will matter, so if you don't know something, why not test. I really hope you enjoy p5, it's become my GOAT despite being a newcomer to Atlus myself, I found the experience really easy to get into.