A 7m mile pace is 1:45. Otherwise known as ok and that 1:45 400 time would be a crawl.
Honestly, if you were going to train 400's, I wouldn't do them in the same workout as gymnastics. At the end, there isn't enough in the tank and done at the beginning they would kill the rest of the workout if you went out hard. You could figure out 75-85%.
If you worked out in the mornings, you could do them in the evenings or vice versa.