Hi Robert,
I searched one of my Grant lists starting at the D&RGW numbers you mentioned. After that, there were no 2-8-0s until builder's numbers 1511-1520. They match your description of where they locos went.
TC&StL 61 and 62 do not have any history so your M&O #7 would have to be one of these two.
[
jennycat.home.mindspring.com]
[
jennycat.home.mindspring.com]
I hope this helps.
Doug