Others like myself might be confused why you are asking this now considering (assuming you're in the US?) track season is nearly at an end.
It matters what level you are coaching and what your individual athletes are like. The answer can be complicated. For example as a high school coach I might have three athletes with the same talent for running the 800. One is a soccer goalie in the fall, one is a soccer mid-fielder, and the last runs XC. You really have to treat each one of these individuals differently in training.
- Our hurdlers practice quite a bit with the sprinters. We have separate skill sessions. Like when the relay is working on baton exchanges the hurdlers will be breaking down components of their race on coach's eye. One day we'll do trail leg drills, the next time lead legs, etc...
- Our long jumpers are usually sprinters also. They are training with the sprinters quite a bit.
- Our long jumpers follow along closely with the sprinters. The days we are working on pure speed like 30 meter sprints our long jumpers might be working on their approaches. We very rarely do real jumping in practice. I have found that most of the long jumpers I have worked with have a naturally good penultimate and final step. There is more of a learning curve with triple so those skills need to be worked on more in practice. Most tend to elevate and overcommit on the hop making the step too short.
- HS athletes tend to make the same critical errors in the hurdles. They all need the same technical work. It's random what skills they struggle with. There is no set answer for this. As an example, If I have an athlete that is 5 stepping it really doesn't matter whether they are 100 meter sprinters or IM hurdlers, we need to work on that 3 step for them to be competitive.
The "art" of coaching is figuring out what your athletes need.
Extra credit: I'm not entirely sure what you are asking but I think it's about convincing your assistants to encourage kids to train during the off season? If the athlete is a distance orientated athlete I try to steer them towards XC. Otherwise your best bet for off season conditioning assuming we are talking about youth is for them to do another sport during the offseason.