weird burning, and other spots i can't figure out

i have a few plants, different ages, but all still in veg.
400w mh, really gentle nutes, 5.6-5.9 ph for the hydro ones and 6.3-7 for the soil. the soil is actually mg for plants and vegetables.

some leaves are drying out and turning brown. some are turning this dry dark green.

there also have been these spots on then that look like bug trails, but they are just random and small. but around the trails these black dots come and then the leaf's usually turn for the worse.

also, found these little yellow bugs on the bottom of a few leaves near the middle of the finger.

When I use MG at times it burnes my plants. not always but it has and it looked JUST LIKE THAT! my plants always survived it though and after a certain age it just stoped and healed and went away. usually around that size.

I think they all look fine. Those leaves will need to be trimmed soon enough anyway. The top 2/3 of the plant will tell you all you need to know about it's health.

im not sure exactly what would be causing the spots, because those are spreading over the newer leaves as well.

looks really buggish, but im pretty new to this so im not completely sure.

bump, im worried about the spots on the leaves, can anyone help me?