Incidentally,
@Ballari , whilst I have personally not actually met somebody with a baby on camino I have seen people walking longer distance trails in New Zealand with babies (generally four/five day treks). The majority used the baby carriers (backpack style with a canopy /rain shelter, as I'm sure you are aware most of the major backpack companies make very good versions of these). They were generally the preferred option, however the trails in New Zealand are significantly narrower than most of the Caminos. 1 point of note is that these of course are only considered suitable for babies over six months old.
As commented by others above, and the couple of videos I have seen many on camino seem to bring a walker's version of those bike trailers, a couple a decent all terrain stroller. The buggies appear very practical because you can also carry supplies for the baby with them and it's not physically on your back. I'm assuming you have some kind of all terrain stroller at home, how does that work for you?
Do you know anybody that actually has one of the other options that you could borrow to try?