Mike:
Regarding the race’s final weeks, there are several different directions the training can take, and their relative value is open for debate. In this case, there is no “right” answer.
The purpose of the longer sprints is to keep the ME stimulus going a bit longer in a more running-specific modality than the gym. As you probably noticed, that plan was written by Mike Foote. He felt this was a useful training stimulus to put the finishing touches on power and muscular endurance. I have used it with runners myself, although it is not my preferred method.
I recommend rolling from the ME block to longer, more aerobic uphill Z3 running. This also helps keep the ME stimulus going in a more running-specific modality but at an intensity that is more similar to the demands of these races.
If you choose that second method, I would keep the 10-second sprints but move them to 1x/10 days, giving you more time to add Z3 runs.
As with many training questions, there is no right or wrong, and you need to experiment with what works for you.
Scott