Not based on your post. There is nothing to do here.

It does not go into a trust. It goes into a guardianship. You need to apply to be guardian of your son for surrogate's court purposes, as well as...

Do the probate. But it is a simple probate, so there is no reason not to do it.

Yes, if he is competent to do so. If not, you will need other work.

No. You would need to do an estate proceeding. Also, if there are kids, they inherit half.

This was a failure of drafting not to have any mechanism for a successor. You are going to have to bring a court proceeding on notice to all next...

You can sign such an affidavit if she will not. State the story you said here.

It depends if there are other heirs to the house or the money. If no, then you can use the funds. If yes, then it depends how the estate gets...

Absolutely you need letters. And more. With multiple states and properties, you need a lawyer. If you do it wrong you risk screwing up the clear...

You can do a subdivision. Talk to a local land use lawyer. However, you will undermine the value of the property this way. I am not 100% sure of...