I would like to get out of the Navy with somewhat of an education as well as training that would be useful as a civilian. What would you do from my options, and why?
AECF, then use the GI bill as GLW posted
Why?
1) Because if you have to ask, you will ring that bell on day one of BUDS. Welcome to the Navy, HTSA. Or better yet, welcome to being administratively discharged and having to find a new job after going through boot camp with no veterans benefits.
2) You will not have the opportunity to voluntarily cross-rate on your initial enlistment. The recruiter will tell you it's possible, and he's technically right and probably can point to a handful of exceptional cases where a sailor was allowed to cross-rate in an initial enlistment for reasons other than being medically DQ or failing out of his training pipeline for his original rating. But I'd be willing to put my $30,000 bonus up to bet that recruiter that it's not going to happen to you. That's besides the fact that you will not be voluntarily let out of the SEAL community to cross-rate. But see #1 - you aren't going to make it through BUDS anyway.
3) Having good experience with computers will permeate into virtually every field these days. At some point, you will have to learn some basic programming for any technical white-collar job (I know that purists won't call MATLAB 'programming,' but I do). Not that an AECF rate will give you programming experience, but it will give you some experience with troubleshooting networks and give you a basic understanding of how they work. Nuke might give you some good experience at a technical trade - and if that's a civilian career you wish to pursue then that will be useful to you - but it won't help you much with jobs/careers that require more advanced technical degrees any more so than the non-nuke equivalent.