Ok, I think I can help here, this is my experience from midwifery school and my apprenticeship. The routine prenatal blood work varies a bit from practice to practice but usually checks the following, this is going by memory, I might be forgetting a few things:
Hepatitis B and sometimes C status
Complete Blood Count, which includes hemoglobin, hematocrit, white blood cells and clotting factors
Rh antibodies and other blood antibodies
In my opinion, the CBC is important to know where you are as a baseline, esp if you might be anemic. Also, it can flag any other odd thing that might have come up. If you have no reason to believe your STD status has changed, that is unnecessary. It is unlikely that your Reubella immunity changed from the last pregnancy. If your blood type is Rh negative, it is important to test for antibodies - even if you got the Rhogam to make sure you are good there.
The lab urine culture could be a couple different things - it could just do what she does in the office on a stick - but more "official" and if there was bacteria present it would then culture it to see what it was. However, it depends which type of sticks she has - some midwives only test for protein and glucose and others test 10 different things. The main thing that would be useful is to know if you have an bacterial infection - some office tests look for that, others don't.
It could also be the gonorrhea/chlamydia urine test - which if you've been monogamous, highly unlikely that you have it.
Some midwives add on glucose, iron stores, thyroid and vitamin D to the blood work. You would need to discuss with your midwife if it made sense for you, to do these.
So, I'd talk it over with your midwife - I think you could pare down the tests to a minimum number that would be important for you in your situation.