Your waters breaking two days before has nothing to do with the position of the baby. However if they broke and nothing happened this time, I think the guide lines are 96 hours before you have to be induced (i.e. in hospital) but many hospital have tighter policies than that, from what I have read on MN it seems most hospitals allow 24 hours before inducing, although you don't have to go along with that.
Lulu might know better from being 'hands on', but I don't think there is any evidence that says that if your first baby wasn't in the correct position, then your second wouldn't be either, I think it is just luck of the draw with each seperate pregnancy. So the chances are this baby would be in the correct position.
The lip on your cervix, I may be completely wrong on this, but I think seeing how you have already been through labour now, things are a bit ahem, roomier down there ahem, (LOL) I'd have thought it wouldn't be much of an issue this time.
How far are you from the hospital?
Many people find with a home birth, the fact that you have a midwife with you, and you alone, and then when things start getting heated you have 2, all to yourself, they tend to get to know how you are handling it all, and are much more likely to pick up on any problems quicker than they would in a hospital looking after 5+ women at a time.
Why don't you, when you are pregnant, talk to the midwife with DP, see what she has to say, and if what she says does anything to relieve his fears? Explore the net a bit, but don't take any of it as gospel, always seek a (professional) second opinion on things you find on the net!
I think the problem you have with home births, and births in general, is that you only ever hear about the 'bad' ones, it is the same for everything, like I moan when the postman comes late, but I never seem to notice when he is early!
You do have to bare in mind there are risks, but in most cases these are outweighed by the fact you have a one-to-one midwife with you, and if home births were as dangerous as many people think, then why are the professionals still letting them happen, and in some areas positivly urging people to have them?
Sorry I have waffled, 'tis a subject close to my heart! Just wish I was brave enough to have one, having said that though, I can see this next one being a very unplanned homebirth!