Cute!
I wouldn’t worry too much about the vaccines. The immune response is what you’re after so the amount of vaccine vs weight of dog isn’t really relevant.
If you want to stagger, that’s fine, but unless you have a pooch who has had issues w/ vaccination, I wouldn’t bother. (I do stagger for my older lab due to a previous reaction, but I do not for my other dog.)
The general rule with vaccs is to wait until the pups are weaned as they get antibodies from mother’s milk if she’s been vaccinated. So vaccinating before weaning is fairly useless. Typically vaccinating at 8, 12, and 16 weeks is good.
Get on the HW preventative soon–some vets will not script out HW preventative til the pups are 4 mos or so as HW preventative treats for microfilaria which means you actually have to HAVE them first and that takes a litle time. But the HW meds will also help with intestinal parasites other than tapes. You mentioned that your pup had fleas, so I personally would get the ivermectin injections and treat for tapes as they don’t normally show up on a fecal and are transmitted by fleas quite often.
Best wishes!