2) You can put aside any notion of going to college while in a/power school/prototype.
Recently this statement has become a little less true than it was in the past. While it is true you won't be allowed to take courses while you're in school, between power school and prototype there has been a backup for some students lately. Beause of the delay, hold students (depending on how long we anticipate they will be on hold of course) are sometimes allowed to take some classes in lieu of working a menial job doing random busy work around the site. This is of course completely on a case by case basis and as the pool of hold students gradually goes down it will go away once again.
As far a OCS packages and the like, i agree with starkist... submit your package early, don't fall victim to people who tell you to wait because you'll have a better chance of getting picked up.
as far as the credits transferring, towards an excelsior NET degree as an ET1 i was required to take around 12 courses but was able to test out of the majority of them. For someone with a BS already you're probably looking at only a handfull of courses depending on what you've already taken as most of the courses i was missing were the core classes that you will likely already have credit for. I know a lot of folks going through TESC end up taking various courses just to meet residency requirements when they could (in theory) test out of it. i'm sure a search of the forums wll yield a wealth of information on the subject.
good luck.