I'm going to go ahead and be the voice of dissent on this one.
3rd one needs nitrogen, the purple in the leaves tells me that. How long since they have has some water? If they have had lots of water recently then wait to water, then the next time they need to be watered give em some nutes
The purple comes from the isoflavonoid anthrocyanin. Anthrocyanin is a plants natural protection from sunburn. Some plants produce more of it than others. In people, that compound is being studied as a cure for certain cancers.
That said, damping off can look like sun burn damage if you've never seen either before. The differences are subtle.
In pictures 1, 2, 4, 5, and 6 it looks like there are dry crispy edges around the leaves... This is usually due to over fertilization.
I'm going to go out on a limb here and guess that you are doing like most everyone does at some point and over loving your plants. IE I think you may be over watering, and over fertilizing a touch. There is also some bug damage.
My recommendation is as was mentioned already, to adhere to the WWW rule when watering: Wait for it to Wilt to Water. Similar advice with the fertilizer. If you are not over watering, and your plant starts to turn yellow, you know it needs fert.
Pepper plants seem to handle the lack of water and nutrients better than they do their abundance.
Good luck!