If I did each full body workouts for mainly muscular hypetrophy every four days would that be too long of rest for optimal muscle mass gains or no? For example:
Day 1: Martial arts training and/or speed training.
Day 2: hypertrophy training
Day 3: Aerobic endurance training
Day 4: Day off
Day 5: Martial arts training and/or speed training.
Day 6: hypertrophy training
Day 7: Aerobic endurance training
Day 8: Day off
repeat cycle
The answer to this question depends on your training history, amount of sleep, active recovery, food you are eating, age, etc.
In lieu of all that information I would say no. Lifting full body once every four days is not optimal for muscle mass gains. Lets look at it this way, do you know any body builders that lift full body once every four days?
In DAY4 you could probably do more hypertrophy training, pretty easy fix.
Depending on your schedule you could probably both lift weights and do martial arts in the same day. Lifting heavy in the AM might actually help your performance in martial arts class later in the day.
There are a lot of things you could do.