Based on the amount of time you stated (1 year), DoDI 1332.38 states:
E3.P2.1. Criteria for Referral.
Service members on active duty or in the Ready Reserve shall be eligible for referral into the DES when the member:
E3.P2.1.1. Has a medical condition that is cause for referral into the DES as established by enclosure 4 of this Instruction or by the respective Service’s supplemental medical standards, and the member has received optimal medical treatment benefits; or
E3.P2.1.2. Will be unable to return to full military duty within one year of diagnosis of the medical condition; or
E3.P2.1.3. Was previously determined unfit, continued in a permanent limited duty status,and the period of continuation has expired; and
E3.P2.1.4. Is not disqualified under section E3.P2.4. of Part 2.
I should speculate that you will be required to process through the IDES. In addition, regarding your PCS orders, you will probably be put on Medical Hold until your are either found fit for duty or processed through the IDES.
On the other hand, you have surgery scheduled and the Army is probably trying to do what they can to make you fit for duty or make you well enough to be able to function once medically separated/retired.
For question number 4, I recommend you ask your CoC to determine what your medical unit is trying to do in your situation because since you are now at the one year point, the regulation clearly states what is supposed to happen.