1500m workout

I wouldn't do 16 of them. I think that is a little too much volume. 8-12 would be my recommendation. You could also lengthen the rest a little if you don't want the workout to be too taxing. Jogging 200-300m in between each one would give you a good approximate rest period.

Both of those workouts sound a little too hard for your third effort of the week. My go-to light 1500m workout is 3-4x(400,300,200) with 100 walk, 200 jog, 400 jog rest. I usually do the first 400 at 3k pace and the main to cut down so by the last set I'll do the 400 a touch quicker than 1500m pace.

Do some 200m,300m reps and some 400m,600m reps