I don't really get the square foot garden mixture. I don't think peat moss and vermiculite offer much in the way of nutrients, and in high concentrations are going to dry out fast. I've been filling my beds with what a local quarry calls "veggie mix", which I think is a mix of top soil and compost and maybe something else. But a reputable quarry in your area is going to provide the best soil mixture for growing, IMO. I top my beds off with it every couple years. Alternate years, I throw in composted steer manure, and I continually turn it into the clay soil underneath to get the mixture deeper and deeper every year. Rarely do I fertilize during the growing season, I only water every few days, even when temps get up in the 90's, and I get good results. When it comes time to top off your beds with new soil, I would really consider trying something different. You might find you don't have to water so much and will get better results.

I don't want to venture a guess as to what those buggies are, but just want to advise a good first-tier bug spray that is cheap and non-toxic... fill a squirt bottle w/rubbing alcohol and squirt in a bit of dish soap, Dawn is good- give it a shake and then spray awaay..... it kills most bugs and you can then wash it off and eat whatever....I keep several bottles out around the garden...I just use bottles that Clorox Clean-up or Lysol w/bleach, etc. came in, after they are empty...sally

It looks like Flea Beetle damage. Keep an eye out for tiny black hopping beetles. They are very fast. The link below has a few options for control(did a quick web search). I have found nasturtiums to be a good trap crop. Here is a link that might be useful: flea beetle control

The youngsters look scary too. They're not too fast but will try to move and evade if one were to reach in and crush them using the fingers.