If the shares were not held with a right of survivorship, then your sister's half goes to her, and the other half is divided among everyone. To...

You can do nothing. The law provides that result. You can deed it to them now, reserving a life estate in yourself. Then they do not have to do...

You can look at the deed. If it is in the name of your aunt and uncle it is their house and not in the estate. Thus, you get zero from it.

There is a petition you need to file.

This is way too complicated for an internet post. There are other options as well. It depends on what she wants and how advanced the disease is.

So the same lawyer handling the real estate transfer should handle the trust issues. The answer is whether the trust has a tax ID number already. ...

Your post is a little unclear on what the will says. I am not sure who "she" is. If it is the judge, and the trust is not part of the will, then...

No, because revocable trusts are not true trusts, and use the grantor's SSN. An irrevocable trust gets its own TIN.

In trying to do it yourself, the errors and delay have caused you to be on the verge of being out-maneuvered. If you have siblings, they are going...

If your letters are unrestricted, then yes.