exclusion of heir

What is the name of your state? DC

I am petitioning to be the personal representative for the estate of my mother, who died in September. There are 8 heirs (there was no will). All but one signed a waiver for bond for my petition. The lone hold out (who had been estranged from our parents for many years) just told me that he did not wish to receive anything from the estate. Do I have to list him among the interested persons? Also, the estate includes a house which we do not want to sell at this time. However, I wish to preserve the rights of all my siblings when it is sold. How does one go about this?

" just told me that he did not wish to receive anything from the estate. Do I have to list him among the interested persons?"

Yes. You will need him to execute a waiver of his rights and file it with the probate court. Expect him to change his mind.

"Also, the estate includes a house which we do not want to sell at this time."

You can transfer the deed and have each heir listed. However this can result in many future problems. Suppose one dies and they have numerous heirs. They could delay the sale of the house and you would lose your buyer. Suppose all want to sell except for one. In my opinion it is better for everyone if you sell and settle the estate or if two or three of you buy the others out.