I looked at this a little more this morning and here are some thoughts I had.
1) You ran a 1:39 half in the fall. That calculates to around a 3:30. Why are you only shooting for 3:50 at Cincy? That race is still 15 weeks away. I think you could train hard during that time and take a crack at 3:35. No time like the present. Pfitz has 12-week programs that you could follow.
2) If you run hard at Cincy, that 20k 3-4 weeks later could be difficult.
3) I believe someone else mentioned this but July 9 to Oct 16 is only 14 weeks, not 18. June 12 would get you to 18 weeks.
4) I don’t have a huge problem with only 7 weeks for base building from May 16 to July 1 because the start of Pfitz’s program is basically base-building.
5) You mentioned reducing mileage after the Aug 24 half. If you’re following Pfitz’s program, the mileage doesn’t really drop. You’d still be in the 50-54 mpw range.
6) For the most part, I don’t mind your racing schedule. Just make sure that your Sept 3 race is truly run at MP – don’t get carried away. Sometimes that’s hard to do when you’re in a race. Finally, I’d take a 2nd look at that 10k two weeks before your goal race. My choice would be to find something a week earlier OR run a 5k instead of a 10k.