but get educated on how the SNA pipeline and airframe selection works before you get your hopes up TOO high on flying F-18s like your profile says.
Couldn't have said it better myself. To answer the OP's questions:
1. The quickest way to never see wings and never fly the F/A-18 is to make it clear (as your post seems to do) that you're only in the military as a stepping stone to the airlines. If you want to fly for the airlines, don't join the military - go to one of the myriad of flight schools, then the regionals, then the airlines.
2. Have goals, but understand that (as has been discussed numerous times before) you are an officer first, pilot second. Leading Marines is what you should want to do, not just fly.
3. 60-70%-ish of all Marine pilots fly helicopters. Prepare yourself for that very real possibility.
4. In the latter stages of flight school, you have the opportunity to take the military competency exam. When you get winged, you will get a commercial license with appropriate endorsements (i.e. - I have SEL, Helicopter, and Instrument ratings for both).
5. After that, there's opportunities to MAYBE get add ons like ATP and what not, but not until you've done 4-5 years in the fleet, and at least 2 deployments. At this point, you'll be looking at almost 10 years in the military, and as soon as you get the extra training - you owe them more time.
6. Alot of the jobs that give you the add ons above are very competitive. Helo guys that are trying to get multi engine, etc... Remember - 60-70% of all Marine pilots are helo guys. So, if it's station flying C-12's or Pedro, or Flying OSO - a good portion of those billets are going to be helo guys. Some specifically require an MOS (Pedro requires 7562), and some require a transition (C-9s). I've known LtCol's with 16 years in, and 3000 hours that have been turned down for some of the "sweet gigs".
Not to piss in your Cheerios, but being a Marine is MUCH more than wearing blues, scoring with chicks, battling fire monsters, climbing sheer rock faces, and flying jets. You will get dirty, sweaty, smelly, and tired. You will say goodbye to your family and friends for months at a time. You will work long hours for shitty pay. You will be told to go to an out of the cockpit tour. You will get fucked over with a shitty billet. But you'll keep doing it because you get to serve with and lead some of the finest young men and women this country has to offer. Your message seemed to indicate that you're only concerned about what you get out of it. Please, don't join the Marines. Join the Air Force.