Hi Diogenesister,
a) Yes that is the most lightly case. However a Trust can also operate while the person who initiated the Trust is alive and well.
b) I have come across a number of Trusts that have donated to the Watchtower organization. There was one Trust that was seeding a plethora of religious organizations including the Watchtower corp. Now unless the Watchtower checked the financials of every Trust from which they accepted benefits, they would not be aware what the Trust was investing in.
I guess the Watchtowers argument in accepting funds unquestioningly would be that a serial ax murderer could walk into a Kingdom Hall and drop money in the contribution box.
"...in theory then would we know if the Watchtower has declined to be a beneficiary?"... I never specifically checked it out. I have always assumed they took the money.