Hi Chara

I grew Cornell Delicata bush last season, it did not do well for me that is the reason that I have not grown again. It probably does best in northern gardens.

Here is a picture of the plant

And here is picked after showing the markings

All my plants are on a spraying program once a week serenade and spinosad, what it does is delay the yellows and other diseases due to the rains and bugs. If I still get a good crop it is okay.

I think that you have the older vinning variety of delicata, I had the improved bush and still did not do well.
And don't worry about the tomatoes, eventually all the tomatoes yellow, some more than others due to various reasons, I have not seen a picture yet of a mature tomato plant with all the green leaves and ripe tomatoes. :)

About the squash I am trying new to me Oriental varieties that are doing well in the heat, they are small in size and grow fast, let me know if you want to try those. I have some in pots and some in a raised bed to see which ones do better. To the delicata you have if you have not added liquid fertilizer, try that maybe it helps, with the rains the nutrients wash away.

Silvia