Shame you're not around here at the mo - be happy to help with your chord learning. Yeah you don't have to play all strings for all chords (and there's nothing wrong with that). Learn the basic shapes and keep practising them until you don't have to think about them. I'd actually argue that you should practise on an acoustic guitar and build strength in your fingers, then when you play your electric it'll be like a hot knife through butter.
Start learning the F-bar chord shape - make sure you play ALL strings for this one. It'll take you ages to get but one day it'll just happen and you'll go "why couldn't I do that before" then you'll be able to play most bar chords.
Drop D tuning is just dropping the tuning of the bottom E string to a D, then you can bar the bottom three strings in the same position and play any power chord by just sliding your finger up and down - no need for the e.g. 1-3-3 shape as 3-3-3 does the same thing. Did that make sense?
Paul Clarke's blog - I live in Hythe near Folkestone. Wed + father to two, I am a full stack web engineer, + I do js / nodejs, some ruby, python, php ect ect. I like pubbing, parkrun, eating, home-automation + other diy jiggery-pokery, history, family tree stuff, Television, squirrels, pirates, lego, + TIME TRAVEL.