Kellogg's makes a range of soil products (who knew? is it the same Kellogg's that makes breakfast cereal?). I don't know which you have, but it sounds like the soil is at least part of the problem and you need to be fertilizing.
Tomato Tone is a good organic fertilizer designed for tomatoes, but there's lots of organic fertilizers out there. Picking something randomly is better than not feeding your plants when they clearly need something.
The other issue would be water. You said you are in Calif? Southern Calif? Does that mean it has been hot and dry? I have NO idea if 20 min in the AM of watering is enough or too much. Is that 20 min of drip irrigation? 20 min of pouring watering on? Assuming these are in the ground, not containers, you want to put water on until it is puddling, let it soak in and then do that two more times. And then don't water again until the top couple inches of the soil dry out.
With the soaker hose, after you have watered, dig down and see how deep the soil is wet. If it isn't wet 6" down, you didn't water enough. If it is wet 6" down, you probably don't need to water every day.
In your first post you asked about "not enough sun?" Are they in full sun? They need at least 6 hrs of direct sun a day. If you are in So Cal and it is getting hot, it is best if that is AM sun, with some protection from hot afternoon sun.
But seriously at least re the squash and cukes, now that you know a little bit more about watering and feeding, I would start with fresh plants. Those have been so stunted for so long, no matter what you do now, they aren't likely to thrive.
Tell us (or show us) what the roots look like, when you dig one up.
Gardening isn't hard, but there are some things you need to know getting started. Perservere!