This cold shoulder business is the opposite of all midos tovos. Perish the thought. Chas vchalila. One can be extremely warm and kind, and still not cross any lines. One should greet everybody b’sever panim yafos,
I mostly agreed with you, up until…
offer to help in any way, ask them how their day is and how their family is doing, etc.
Helping with boundaries is no problem, but helping “in any way” is, since college students frequently blend social and academic activity. Think, “can we study for the exam over dinner?”
The remaining examples risk crossing the boundaries of professionalism. One can be approachable and friendly without discussing details of personal lives.
If I were back in college, I would try to reserve most interactions for the in-class setting, and pick same-gender lab partners.