I have no proof as to the date of Elizabeth's death, I just happened to come across this information.
My husband's ggmother was a Daniel, and some years ago I started researching Alexander and his family after we found an old letter from my husbands gmother giving information on her ancestors in Cornwall.She indicated that she was descended from this family and said - "Ma could name the decendants(sic) right down to her father".Unfortunately I haven't been able to prove this, but everything else she said I found to be correct.
I have gathered information on a lot of the Daniel lines hoping to find the missing link.Thomas died in Truro in 1793 I think, but no date or age shown, and said to be born in 1715 the gson of Jacob...Jacob being the son of Jenkin.Jenkin being the brother of Richard who is Alexander's father.But as you say there is more proof needed and nothing obvious for Thomas' birth at that time in the Records.
Have you got any of the Daniel family information written by the early historians.?I have quite a bit, but I know of some things I don't have.There is a little conflicting information re Alexander though in a couple of pieces.
I have only 16 children for Ralph Allen Daniell which includes 4 that died young.Also found a lot of descendants and it is all very interesting.I have information on the family of Ada Eliza Groves who married Edward Daniell here in 1869 as well.Edward and Ada had 3 children here, but 2 died.
I have become quite intrigued with all the Daniels, and would love for us to to share our findings. It will have to wait until after Christmas now for me to get all my notes typed up for you as this is a very busy time of the year. Would like to hear back from you though,... maybe email me direct.