Is it possible to go Green to Gold as an AGR soldier?

Green to Gold is a Regular Army Active Duty program. You can still go to college while you are AGR but you will have to go on your own. I was in the National Guard and went to college online. The issue is that while you are in the Regular Army you will incur a service obligation when you go Green to Gold. The Reserve components don't work the same way. There are programs out there for going to college while in the Reserves, like the Simultaneous Membership Program, but I don't know of any programs that cater to AGR going to college. Even if you did go to college you would not be guaranteed an AGR position.

From my experiences with this question, nobody really knows. I’ve asked universities and HRC but never got a direct answer.

Lots of gaps you are not clear on. Like what kind of AGR? State AGR or Federal AGR. At the state level or ARNG/NGB? National Guard or Reserves?

You can go Green to Gold (enlisted to officer) while an AGR. However, you may have to leave your AGR position. There are no 2LT AGR positions but you may ask for an exception to policy (ETP) to come back on to AGR. Highly unlikely unless you have a special skill set. Same for transitioning to warrant officer. There was a time when it was allowed but not anymore without an ETP. So it can be done but you will have to give up your AGR status. You cannot do ROTC while you are an AGR. You cannot be on two contracts at the same time.