Kevin Prevost and Hazel's Family Tree

When I visited Hazel Prevost and her family, Hazel let me know that her nephew Kevin had been doing some research on the family tree.  In an earlier post, Hazel shared her view of how the family grew and developed in Jackson Creek.   Hazel shared this version of our family tree which was researched by Kevin.

Family Tree Info From Kevin Prevost

I believe the questions we have are:

1. Who was Thomas parents? Kevin views that is probably Alex who was likely Samuel's brother.  Can we confirm that with records and sources?
2. Can we confirm William Alexander was Thomas son?
3. What was the relationship between Alex, thomas, and the two Samuel's who were early american settlers in the mid 1700s?  Brothers?  Sons?  Cousins?
4. How did our original ancestors get to America?  Was it through Delaware as Saumel obviously spent some time there (wills witnessed and records there)?   Or was it through Charleston and French Hugenauts as Hazel thinks?
5. What was the connection with Illinois in the 1700s?

We will keep following the clues.