How do you can escape the arm triangle choke?
And also how would you escape the figure 4 body lock?
I can't ask my BJJ teacher, because I haven't been there in 3 months, and I'm not starting back until December.

Heh. I got caught in one of those the other week. Don't let your arm get caught! Keep those elbows tight to your body if you are trying to pass guard. My instructor always tells me "Keep both arms in, or both arms out" - never one in and one out.

No idea with the body lock. Maybe try to turn in facing them, but really, don't let them get it on you in the first place.

You can't let him get your arm tightly sandwiched in between his head and yours. Put your palms together and push to create space. Shoot the trapped arm over your head and down in front of his face so he doesn't dig with his head and pick it up again. Be prepared to defend your arm.

The fig 4 body lock is a pain in the a$$ if the guy is good and you have to figure he is good if he put you there. No easy escapes from there. Defend your neck.

I was watching this UFC match (I forgot who were fighting), and one of the fighter submitted the other by only applying the figure 4 body lock, he didn't even choke him to submit him. Thats crazy

Depends how out of gas you are and if they have it on good, then it is hard to take a deep breath to try and breath and recuperate and fight back. It is all down hill from there.

Arm triangle defense is pretty easy, swing your legs up so your knees are near your head and grab around your legs with both arms, that'll relieve pressure on your neck.

Figure four body lock from behind, you want to get both of his feet between your legs, and then work for a standard back escape.

Figure four body lock guard, step your leg over his shin and drive in, you'll make a calf crank out of it and he'll have to release his lock.