It's highly unlikely the Marine Corps will waiver you in with an RE-4 (which you'll have as your RE code if you have an OTH). It never hurts to talk to a recruiter and see what they can do for you, but you probably shouldn't get your hopes up.
Choose not to re-enlist (honorable discharge), bad conduct discharge, hardship discharge, medical discharge, die.
An honorable discharge is the way anyone gets out of the military unless they are kicked out. When you enlistment time is up and you don't want to enlist again, you get a notice of honorable discharge from the Army.
You can always re-enlist with an honorable discharge. Also, being gay is no longer an issue.
A COG (Convenience of the Government) Discharge is the government's way of backing out of its commitment to an enlisted person without doing harm to that person's future. They are most often used to cancel the contract when the recruit is injured in training to the point where there is a long recovery time or a full recovery is not anticipated. It is a "good" discharge so long as the word "honorable" is attached to it. With an honorable discharge a person is able to claim military service and, in many cases, even enlist again once the physical problem has resolved itself. He is also most probably eligible for a 5-point Federal Civilian Service hiring preference as a veteran. It is an administrative discharge (as opposed to a judicial discharge like a dishonorable or bad conduct discharge).
No.
No. A dishounourable discharge bars the serviceman/woman from re-enlisting.
Retirement nets you an honourable discharge, but not all honourably discharged personnel are retirees. If you enlist for three, four, etc. years, perform your duties like you're supposed to, and decide not to reenlist, you're discharged when your contract expires. You receive an honourable discharge based on the character of your service. Someone who retires still receives such a discharge, but now we're talking about someone who has reenlisted multiple times, and will be collecting a pension.
It is unclear what you might get credit for, but no. You get no credit for previous discharges honorable or otherwise in the event of an eventual Bad Conduct Discharge. having served in the military, you must be aware that the last record is the only record. Your only hope to erase the bad mark is to check the "R" code on your DD-214, and hope you do not age out before you can re-enlist and clean up your record.
No. It is possible to enlist in the U.S. Army if you are a legal resident but not a citizen. In the years following World War II, citizens of the Philippine Islands could enlist in the Navy and become citizens of the US. My own grandfather, an immigrant from Greece, enlisted in the US Army in 1917 and served in France. He received his honorable discharge and his American citizenship at the same time in 1919.
Go to your CO and request a discharge...or just don't re-enlist.
No, they do not recruit illegal immigrants. They don't allow them to enlist in the armed forces. You must be in good standing to enlist.
You'd have to look at your RE code on your DD-214. If it's RE4, you can pretty much count yourself out, and they're not likely to want to take the time to waiver you in with an RE3, either.