Can't comment on the blood pressure, but for the breech I think it very much depends on why your DC was breech.
There are a very small number of families with a genetic predisposition to carry breech (there was a family tree in a book I was given to read when DD was breech ["Breech Birth" by Benna Waites"] that covered 3 or 4 generations and showed something like 70% of the babies were breech!). If you have a family history of breech babies then it would be more likely. This is thought to be related to maternal pelvis, but it's so rare there hasn't really been any research.
A bicornate uterus can make it more likely for babies to be carried breech as it's hard for them to turn, but they should have identified that with DC1.
I think most other variables would be child specific - reasons I've seen for a baby being breech include position of placenta, length of cord, baby wrapped in cord a particular way or, as I think happened with my DD, baby just got too big for the space available before getting head down.
The only other one that might repeat would be postural issues with the mother - if you have an asymetry in your spine or pelvis that effects the musculuture around your uterus and can make it harder for baby to turn. If you're very concerned then get to a physio/osteopath/chiropractor and get yourself checked out.
It's certainly far from given that you'll carry anymore babies breech - I've a friend with 4 DCs: the first was a CS as breech, the other 3 head down VBACs.
Good luck