Your Morgan died in 1808, and my Evan was born around 1826 so it was probably a long shot. Being way down here in Australia I have no idea where the towns are in Wales. My Evan says he was born in Aberdare, but I recently watched a WDYTYA? show and it was set in Llangyfelach, then I saw you were researching the same name and I thought it might be worth a try. I would imagine from the UK perspective ancestors that migrated to Australia would look like they dropped off the face of the earth. Down here we at least know that if we can't find them in Oz then there is a very good chance they migrated from the UK.
Anyway, would love to see your tree, although I am not expecting to make a link. My email is firstname.lastname@example.org
Thanks again. Good luck with your research. Karen