800m, 1600m, 3200m needed for sub 16 5k

Can't really speak from a cross country perspective because every course is different, but in general if you are training sufficiently, 4:40/10:00/16:10 1600/3200/5000, give or take, match up pretty well on the track. To achieve 5:07 pace in my opinion you'd have to be 4:37/9:54 in the 1600 and 3200. XC? I wouldn't worry too much about times.

It depends on the course and the runner (especially with the 800, that's a very different race from the 5k). When I was a senior in high school, I ran 16:08 in the 5k (on a fast cross country course in the fall), then 4:39 and 9:48 on the track in the spring. I never ran the 800, but I probably would've struggled to break 2:10 lol

ran 15:59 on grass then 2 weeks later did a 3200 TT on the track in 9:53 off a 5:05 first mile. my mile/800 PRs at the time were 4:36 and 1:57 but I figure I was good for ~ 4:30ish and 2:00 ish on the same day. something in the range of 4:30-35/9:50-55 is probably where most people would fall into. 800 fitness has basically nothing to do with 5k fitness so maybe like 2:08?

I am thinking back to my high school days (circa early 2000s)

My senior year there were only 2 kids capable of running consistent sub 16s in my state, that winter/spring they were running 4:20-4:25ish in the 1600 and 9:20-9:30ish in the 3200. The spring before their senior xc season they were in the 4:30/9:30 range, finishing just out of place for a medal at states

Minimums for sub-16 on a track 2:15/4:40/10:00 with great endurance. Faster for sub-16:00 XC. Going to be hard for a HSer, who isn't aerobically developed, to run sub-16 off of those PBs.