Weird issue

This is a 5 week old Northern Lights autoflower that I'm growing, this is also my first attempt at growing. So far everything has been ok, though it does have some strange staining on some of the leaves and also some lighter colored splotches on different ones. I suspect this could be from spraying the plants with hard water (my mistake, i have switched to distilled water for foliar sprays). Some of the stains seem to wash away when i spray them with distilled water. The tips and serration tips of most leaves are turning slightly yellow, but the yellowing is so small it is hard to spot. I suspect this to could be nitrogen toxicity.

I'm growing this plant in a mixture of soil and peat with some used tea leaves sprinkled on the top.

They look very good, in the second picture you could have the beginnings of some critters, my guess is thrips. It's not bad, and unless it progresses I would wait to treat it (confirm if it is actually thrips and not from the foliar spray). The different colors on the leaves in pic 3 is normal and nothing to worry about. Pic 4, your guess is as good as mine, but again unless it progresses I'd do nothing.

Looks like there some kind of dried droplets on them too.

Wouldn't hover over minor blemishes unless it becomes plant wide issue.

Thanks for the feedback, I have killed a couple tiny fly like things so now I'm confident the bright spots are from them. Spots like that in pic 4 do seem to clear up a little bit when I wash them so I think it might just be salt or something.