Question 1 has been discussed here several times and can be found by searching.
For question 2, what above units are you referring to? If it is AD vs. NG, again, it has been beaten to death here, some threads made it into the TS's Office, IIRC.
Question 3 has been brought up as a point of contention, I think anyone looking at the casualty lists and deployments will see the answer to that pretty quickly. Clearly, if you want to be a full-time soldier, AD is the way to go. If you have or want to have a civilian career, you would opt for the NG. That was not rocket science.
The SF officer routine has been answered here repeatedly. Look it up.
Yoiu sure do seem to be planning pretty far down the road for a guy who hasn't made it to Basic yet, much less selection.
TR