Owen and Richard Thomas might have been somewhere else besides Rochester before 1907. I looked for Richard in the Rochester city directories working backward from his known address in 1915.
This is the earliest entry I am sure of:
1911
Richard Thomas, pictures and frames at 48 James, lives there also
These might be him, based on the occupation.
1907
? Richard Thomas, stonecutter at 54 Plymouth, boards 26 Elm
1909
? Richard Thomas, stonecutter, boards 14 Eckhardt Place
Come to think of it, I don't remember seeing a Richard Thomas, stonecutter, after 1911, but I'd have to go back through them to be sure. I think it would have got my attention since his father was a stone mason.
I didn't see Richard in 1904, 1905, or 1906. I didn't look any earlier than that.
In all those years, the only Owen Thomas in Rochester was an insurance salesman with his own company. I ruled him out.