Should the will be supervised? Does he have a deadline with regards to providing beneficiaries with a financial accounting?

You should meet with an attorney to discuss having him removed and have the court appoint someone else. You are entitled to a copy of he will and...

What steps can we take to have him declared dead through the court?

You can petition the court because he is presumed dead because he has been missing for more that 5 years.

Where will my will be probated at the time of my death ans does the state my drivers licence is in make a difference

Agree-main probate in CT and ancillary probate in Florida. You can avoid probate in both states with a Living Trust.

Can the appointed legal guardian be both guardian to of person and estate. Or is it just one?

Yes-can be guardian of person and estate.

How long does a Petition for Instructions in a trust administration take?

I agree with posted answers-no usual time frame and impossible to predict.

What are my options if my younger sister fraudulently emptied a POD account which she was a beneficiary on?

Some of your options- Confront your sister to make it right- If that doesn't work-report to police

Selected as the best answer

How is it determined what State an irrevocable trust is in?

The trust would need to be reviewed to determine what State Laws would govern-I would guess NY where it was drafted.

Do I need a lawyer to do this and what exactly is needed in order to put this document into her trust?

Joint tenants with right of survivorship means it goes to the survivor and it is not needed to be placed in the trust.

Upon our death, will our investments with designated beneficiaries (over $150 T) be subject to probate?

I would vote with your estate planning attorney-no probate with named beneficiaries on accounts.

Due to conflicting answers please clarify-would all assets go to post-deceased wife's estate or to some distant living relative?

Wife's estate is the correct answer.