And it could well be that I start off with flying them including a P2 initially
Van
That is my one reservation as your kids are the most precious of cargo.
In an aircraft they are totally reliant on you should you get it wrong or become unwell.
Taking them up with a safety pilot with more experience could be a way for you to convince your ex that all is well.
When you feel more experienced and comfortable by then I am sure she will too and you can start flying them on your own.
Pace