The problem with your first question is that while the answer is no, you can’t get pregnant while having your period, the other side of that answer is that you can’t always be sure that you’re having your period. You may be expecting your period, you may see a little blood and assume your period has started, but it might be a false alarm. Then if you had unprotected sex, you might get pregnant. So if you really don’t want to get pregnant, always use contraception when having intercourse.

As to your second two questions, if two people want to give each other sexual satisfaction, or at least one person, then rubbing up against each other with clothes on, dry humping, is perfectly all right and since the object is sexual pleasure, it is not only OK that your boyfriend have an orgasm, but the whole point of the exercise. And, of course, you can’t get pregnant this way. Dry humping is much less likely to produce an orgasm in a female. Assuming that you would also like to climax, he should use his fingers, and it can be through your clothes, to give sufficiently stimulation to your clitoris so that you have an orgasm too.