What came to my mind is that something saw an opportunity to cause problems and used the baby carriage as an excuse. No baby is going to pretend tobe the homeowner IMO. I would get rid of that carriage first and then start smudging daily , lots of smudging daily until the thought of bothering them doesnt occur to the whatever it is. If that didnt work I would go to a priest and ask for a house blessing. BTW Ive spoken of the house I had when I was young. We had it blessed and it did NOT help. The priest who did the blessing was not very convincing and soon after he quit the priesthood I heard. Not because of my house( I hope) but becasue he lacked faith. Which I can understand. He was a nice guy but when I told him I said a rosary daily he told me that was only a mantra and to find another way to pray. I got a strange vibe from that and remember it to this day. There are many ways to pray and the one that works the best for you is always the best for you and not necessarily for others.