3. You only need the first Hep B to pass the medical, and can have it (and any other missing vaccines) done at the medical. Both myself and my husband had the Hep B and were fine, we got our second dose before we left the UK and then our final dose (it's only 3) is being done in the US soon. Our children (age 16 & 18) had the joint Hep A and Hep B at the medical, but be aware that they give children a different one in the US, so they can't complete the course here. We're getting their final doses done at Christmas when we return to the UK, our son needs both for travelling with school next year anyway so might as well.
All 4 of us were absolutely fine after our Hep A's and B's, and we each had several other jabs at the medical too. No side effects although as a fellow needle phobe I feel your pain on that front! I'm just glad I didn't need to have a blood test as well (only our daughter did).