Help on what these marks are

Could be just nicks and bumps. Lower leaves dies off as bigger one develop is normal. In any case, your are growing haze hybrids and you should prepare incase there will be bugs attack down the line. First decide on a strategy. Then get your anti-insect regimen ready. For me, I spray microbes to handle bugs. If you have spider mite infestation, there won't be many days left before plants are ruined. Haze usually have strong resistance to mold. Also your humidity is low. So, I would not worry about mold in your grow.

If it's only one ding on one leaf, I'd say it might be a finger nail nicked it.

yeah, think something took a nibble.. no big deal if it didn't like the taste, lol.

seems physical in nature -- such a straight edge on one side of blotch...