So i have gotten 3 companions, Cass (on accident, i was evil, she hated me and left to go west), Raul (at casino 38), and Rex (with me).

I can't not get into ceasar's tent to continue the main story line, guard keep saying i can't have anyone go in besides myself.

Things i have tried in this order:
Set Rex to wait
Set Rex to wait outside line of sight
Set Rex to wait outside camp
Sent Rex to casino 38
Sent Rex home
Sent Rex and Raul home
Waited 2 weeks game time
Tried to stealth into tent
Tried to stealth kill the guard
Tried to stealth kill the guard with silenced weapon
Tried to stealth kill the guard with a grenade
Sent Rex and Raul home, but literally walked them there to make sure they got back
Killed Rex and Raul

So ya i am out of ideas, 40+ hours spent and now i can't progress cause of a bug. I lived with all the other bugs, save files deleted or missing, items stored in the penthouse disappears, game crashes, slow frame rate, and ect ect. Now though i cant even go further.

Bump for 40+ hours wasted.

You're on PC which is good. I ahve a mod that'll be available within the next few days that has a way to set all follower hire variables to zero, it should clean up the mess for you. It is called FoNV Phalanx. I am still working a few things out of it though.