Can you apply to Green to Gold while active duty to be a Reserve or National Guard officer?

Yes, you can access in a reserve component if you are accepted into a Green to Gold program and complete ROTC. Green to Gold has 3 options, scholarship, non-scholarship, and Active duty option (ADO). ADO would require you to go active upon completion. With the scholarship and non-scholarship routes, you can request a reserve component as part of the accessions process at the start of your final year. Ultimately, it comes down to the needs of the Army and there is no absolute guarantee of reserve component. However, in my 7 years of being a ROO at an ROTC program, I never saw anyone get forced branch into active duty. FYI, as a minimum, you will need to do 2 years of ROTC and full time college classes to complete that. Good luck!

There are three G2G Programs and two of them separate you from Active Duty to go to school full time

They would not award you an active duty scholarship to commission into the reserves. There are scholarships that do not specify if you commission AD/NG/Reseves. Also keep in mind that you could use your GI Bill to fund your G2G route, but regardless, you commitment to the army will renew upon commissioning. 4 years for active and 6 years reserve/NG.