jjrosselle,
I am a cousin of your's (distantly). I am Brody James Ewart, the son of James Scott Ewart, born to James (Jim) Ewart, son of Everett Ewart. I found your post very helpful. Was curious if you could trace the Ewart's from Williamstown all the way back to Josiah?
Also curious, you mentioned Thomas from Ireland my family always said Scotch Irish but had us pegged to be from Galloway or southern Scotland. Interesting ..,