If you are Dawg's sole benificary, his prtfolio will be yours Bobbie, and you need to notify the PRO he used of this fact.
If there are multi benificaries, and it is not stated where his songs go, the execator, should be entitled to make a decision on that matter.
Done in consultation with all benificaries i guess.
Re Chris dasch.
Bob Young did the last collab I know of with Chris so he may be able to help on that one as they were talking cut on that one last i heard.
You may be able to trace John Bizzak through the prison service, as, if i recall right, he was governor of a prison, and i would think they have a record of where he is or was.
Sadly, quite a few of the collabs I worked on did the disappearing act, but as i always worked on a me one element, them the other re words or music, I just went ahead and did a new take of whatever part they contributed to the venture, and put it out solo.
Graham

http://www.soundclick.com/bands/2/grahamhenderson_music.htm