I have a bit of a mongrel house in coastal Southern Maine. One of the basement walls, 24' or so, is a stone wall that's long-ago lost it's mortar and is severely bowing inward from horizontal frost heave. The rest of the basement is a poured concrete wall, so I'm considering supporting that sidewall, trenching around the outside and then pouring footings and building a new wall with ICFs. Looking around, I haven't found much info on how to build with ICFs under an existing structure. Any tips or advice? Can you fit the last row flush to the bottom of the timber sill joist (Assuming I'd need a PT plate affixed to the bottom of it for rot resistance) and somehow still do your pour through some sort of funnel system? Or is it better to end the ICF wall a course shy and then block/brick up the rest of the way? Any guidance or opinions are greatly appreciated.

I had the house lifted by a house mover dropped a plum bob down from the corners built up within 16" of the house and scribe the last row to fit the house above.
I was one of the easiest builds I ever done.