I frankly think you should be way faster than you currently are. At the beginning of March a few years ago I raced a half marathon in 1:21, and did workouts similar to your 400 workout in effectively the same times. I definitely didn't have the same endurance as you for a tempo run, I could only get through 5 miles at 6:10 at a decently hard effort. That year I ran a 4:45 and a 9:52 (I have like no speed at all, way better at 3K and 5K). When I was running 5 flat I used to run 10:30 mids, so right now I'd say you're definitely 10:30 shape. Give it a few more weeks and a solid taper, I'd project a sub-10 in your season this year.
A big workout I ran in between in early April (I ran my 9:52 in mid May), was 10x400 @ 70s with a minute rest. If you can run something like that, I'd say you have a good shot.
*jk lol I just realized its already really late* I'd say for the 1600 go for 73s per lap from the gun, about 4:52 pace, and for the 3200 start with 80-82s laps (5:20-5:28) and then start cutting down hard for the second mile. You want to have enough to go at 600m. 10:20 shouldn't be out of your wheelhouse.