Wanted to update this & thank everyone again for their input. The lawn was seeded on 6/28 so it's been about 18 days. I had some real concerns about possible erosion but with the exception of the first night we had very little rain for the first 8 days or so which allowed me to control the amount of water it received. Had a 2' x 40' area in front of one of the downsputs that empties into the yard wash out the first night. Repaired it the next morning & ran a temporary drain line to divert the water after that. Lesson learned on that one.
While the yard hasn't filled in as much as I would have liked I do think it will eventually. Going to evaluate this weekend if I should go ahead & slit seed it again now or just wait till next year?