I am a new RN (I just graduated in May). Please don't second guess going to nursing school. I LOVE my job, I enjoyed nursing school. I am proud of what I do and the profession of nursing! Not many careers gives you the power to save lives and make an impact on people the way nurses do

The HepB vax is up to you. You just need to go with what your most comfortable with based upon your research. I declined the vax for nursing school. I work in the Pediatric ICU (PICU) and I'm not really at risk for HepB at work (though a nursing friend of mine did contract HepB from a needlestick from a neonate so it can and does happen anywhere). If I worked in our ER which is a level 1 trauma center that gets a LOT of homeless, prisoners, mentally ill patients I wouldn't think twice about getting the HepB series because of lot of those patients have HepB, C, HIV, etc. My husband is starting the police academy in January and I would expect him to get the HepB series, I would if I were him---way to much of a risk.
You should be able to decline HepB for school and work--a lot of people do for various reasons. MMR I would first get my titers checked. The hospitals will require you to have immunity for MMR and chickenpox for sure, no way around that--they don't want you to ever be at risk for transmitting those diseases to your patients, because your going to see some very very very sick patients who catch anything and everything. Titers will work and more than likely yours will still be positive (I was shocked that mine all were!).
I was giving SQ, IM, blood draws, etc my very first semester of nursing school! THe only thing we couldn't do were IV drips or IV push meds. Every school is different with that though. You will definitely be doing a lot of FSBS on all sorts of patients.
I don't worry about putting my children or husband at risk. I come in through my garage and I take off my scrubs in the laundry room as well as my shoes (which I only wear at work). I take a shower and I'm fine--family is not at risk. If you just do something simple like that your family will be fine.