I was under the impression that it'd be fine to be on a Tier 4 visa and stay a bit longer than classes ran, as long a I was out before my stay reached 6 months. Is this completely correct?
If your course is 6 months or less, then you can stay in the UK for 7 days after the course finishes.
If your course is between 6 months and 12 months, then you can stay for 2 months after the course finishes.
If your course is longer than 12 months, you can stay for 4 months after the course finishes.
A friend of mine will be studying abroad in Oxford, and she told me due to the fact that Oxford's semester are short-ish, she doesn't even need a student visa. This is not the fact for me, correct?
Also, the website for Queens indicates that it is okay to work part time (less than 20 hours a week) with a Tier 4 visa. I read somewhere else that it's not okay now, and now I'm getting really confused. I understand I cannot rely on the income I'm getting for money to live on. Really, I just want to do it for the experience.
If the course is 6 months or less, then you don't need a Tier 4 visa, you can just get a student visitor visa issued to you at the UK airport when you land. However, you are not allowed to work at all on a student visitor visa, so if you wish to work during your time in the UK, you need to get a Tier 4 visa anyway. With a Tier 4 visa, you can work for a maximum of 20 hours per week during term-time and full-time during vacation time.
Even if I cannot work for money, is it okay to try to find an unpaid internship or volunteer work while I'm over there? I do plan on moving to N. Ireland on a spouse or fiance visa in the future, so I'm quite worried about creating problems for the future.
'Work' in the immigration/visa sense, means absolutely no work at all - this includes unpaid volunteering, babysitting, working for a US company from your computer, paid employment etc., so no, you wouldn't be able to do this if your visa did not allow you to work. However, a Tier 4 visa does allow you to work, so this shouldn't be a problem (it would not be allowed on a student visitor visa though).