Well, it certainly sounds like you have a good support network around you and have thought carefully about your plans, so I hope all goes well for you.
The one thing I would caution you about is your plan to pop the baby out in the Easter holidays and then be back at school 2 weeks later. Firstly, only about 5% of babies arrive on their due date, there's a significant chance he/she could be early or late, so don't set any plans in stone! Secondly, 2 weeks is a VERY short recovery time, especially if you have a C-section or a difficult birth with tearing etc. It's not enough time to establish breastfeeding, and if you do go back to school for full days, you may well not be able to do that anyway because of the length of time you'll be away from your baby. You may well not be physically or mentally ready to go back into school, especially into your final exam term, within such a short period (which will of course be shorter if baby goes overdue). That's before you consider whether you'll be able to stay in school right up till delivery - it works fine for some people but for others it's just too physically difficult in the last few weeks. I'd suggest talking to your tutors in a few weeks about your plans, and have a backup of deferring your exams/uni place if necessary.