Conifers in general have odd and various growth patterns, and depending on the actual variety, you may not see much regrowth for awhile. Especially as they have been overly neglected already, they have to put their energy into roots and stem before new branches.

As to lack of water, trying to feed them can actually be hard on them as well, if you do make sure its a very dilute dose.

You could try cloching them to keep the air humidity higher (like the 'water tower' thats open on top as you are in a hot climate) this also increases the CO2 to get their aspiration cycle going again. Basically make a poly tube around the tree, tight to the ground surface, as high as you can go (CO2 is heavier than air), open on the top to keep it somewhat ventilated - basically a chimney effect.

If you really want to green them up for looks, give them a good foliar feeding.
A trace amount of Seaweed Extract and Boric Acid, 1/4 C Corn syrup to a gallon of water.