I grow all my stuff DWC. You may want four systems, or to include the Peppers in with your herbs.

There are many really good nutrient solutions out there that work all around for many different plant types. If your into organic, there are organic based nutrients available also.

I use the General Hyroponics Flora Nova series of Grow and Bloom which do not require what they call micro nutrients. I use the Bloom on peppers because they do not like nitrogen. In fact they can grow with basically none at all from what I have seen. Peppers also need very very low levels of nutrients like your herbs and lettuce.

Since you are growing in containers, you could put your herbs and lettuce into one container, peppers in another and tomatoes in the last.

Tomatoes use huge amounts of water and nutrients compared to other plants. You can run the EC for tomatoes from 1 - 3.5, although you can go higher. Peppers are like .30 - .75 EC, which are the same for most herbs. Also herbs like Basil grow super fast in hydro, so give them a separate space or they will take all the light.

You could do a four container system with herbs in one, lettuce in another, peppers in another, and tomatoes in the last.

I buy my nutrients locally so I do not know of a good online supplier.

You have chosen quite an array of cultivars. If you are intending on using the same nutrient solution for everyone, might I suggest it be from an "organically-based' source. That means something other than just a bunch of "salts" added to water (which WILL work, by the way--just harder to control).

Organic-based nutrients will naturally "self-buffer" due to the presence of micro-organisms.

Once you've decided on a nutrient, check out the EC and pH growing requirements for each cultivar you're going to grow and feed each plant within its required range. Click on my profile and go to my Website, then search for "chart" and you'll find each one. Do not attempt to grow everything at the same nutrient strength or pH -- it just won't work!