1) What are my options with regards to progressing in my training or getting around this underage issue besides having to stop flying for 5-6 months?
None, you have to wait. The FAA can waiver anything, but you aren't going to get them to waiver this. Why do you think you have to stop flying?
2) If I started my instrument rating training, would i be able to satisfy the 50 required PILOT IN COMMAND solo cross country hours required
to get the rating by merely solo'ing using my student pilot certificate? I am not sure if I would qualify as the PIC. Imo, I would be PIC for the flight although technically, I do not have the final authority since my instructor he signs me off for each cross country and is responsible. I'd appreciate it if someone could help in interpreting the FAR's for me.
Only a judge or FAA general counsel can give an authoritative interpretation of the FARs, IMO. But I would say your time as student pilot would count as PIC. You are PIC by regulation and there is nothing to say that student PIC doesn't count for experience when applying for an instrument rating. Of course you have final authority if you are solo as a student, if you have a problem in flight you have authority to ignore the FARs as you see fit (but be prepared to tell the FAA why, and they have authority to remove your ability to fly again). Why not call your local FSDO and see what that have to say about it, or even better study the FARs. You should be able to explain the FARs to the examiner when you take your test.
Why do you want to rush?