Welcome to Eorzea!

I don't do endgame so I can't really comment on the communication thing, but I can definetely help you with the side question.

Yes, after ARR's original story dungeons started becoming very linear, as in, they are basically just now one long corridor with some bends or twists, so you have little worry about getting lost (this was to help simplify things and make dungeon runs quicker. It also greatly assisted the implementation of NPC party content in dungeons such as Grand Company Squadrons and it's successor the Trust system/Duty Support). So going forward you do not have to worry about getting lost in a dungeon, just be aware if you're doing dungeon runs through Duty Finder parties will generally wish you to go pretty fast - if you tell them you're new and still learning they may allow you slow down a bit though, so you shouldn't have trouble (it took me years to finally get the hang of running dungeons).

Either way, welcome once again!