Welcome aboard! I'll try to answer your questions best I can:
1) Don't believe you have to have them in a case, but it would be best. There was another case of a man that had his guns wrapped in a towel and that was found to be OK. All long arms definitely have to be unloaded when transported in a vehicle.
2) OC is OK when carrying to pick up a student, but I believe you are not supposed to leave your car. Hence, you would have to have a CPL anyways, as you are carrying in your car.
3) The only rules regarding firearms on college campuses apply only to students. K-12 is definitely a no-no, but colleges are not included in the RCWs. WAC codes only apply to enrolled students and there is text in there banning firearms on campus. I wouldn't expect to get away with carrying on campus as a non student though.