The baby died and the ghosts looked after it too dark
Alison and the baby died in a car crash in the way back from the hospital too dark Mike survived but a head injury meant he could see them all. He got insurance money and could afford Button House and stay with them all.
They all died at the end and stayed at Button House with the ghosts. I thought Mike would be good friends with Robin and Pat. Yes, the aging thing then headstones then all the ghosts shouting "Mike!" as he entered the room
Someone bought the house but asked Mike and Alison to stay on as 'house and estate management', and rebuilt the gatehouse for them. okay
They discovered an amazing 'Neanderthal' something in an archaeological dig and opened the estate as a cultural attraction. Allowed them to stay in the house, partly converted to cafe/museum- potential for further ghosts. okay
Others on here had said Nativity scene/sure they could have worked out a tableau with new born in it somewhere
Others thought Julian's investments could pay off - this would have enabled them to stay
Near death in birth - enough for Alison to be among the ghosts for a short while before they returned her to the land of the living - would have needed an immaculate script
But annoying MIL for 2/3 of it then Alison leaving - nope, nope, nope
The only redeeming feature is a spin-off movie set in a hotel with the ghosts, but even then it doesn't do it for me personally.