I'm following because I'm in SoCal too, and I never know if I'm overwatering or underwatering.

The most important place to water newly planted specimens is the original rootball. You may want to supplement with handwatering for a while.

It's hard to give a strict schedule because there is a lot of variation with changing temperatures and wind. Water new plants more than well established plants, and water when the soil is dry. Mulch will help keep moisture in the soil. If you're in doubt about watering, stick you finger in the soil or buy a moisture meter you can stick in the ground every few days.

You plants may be small now, but it won't be long before they start growing. You may have to move some to another location. Even a dwarf Tecoma can get quite large, the bougainvillea will take up more space as will the escallonia. Or you may have a lot of pruning in your future.

Since the total area of the newly planted bed is not very large, I'd be looking into getting some temporary shade set up to help the plants cope. Water amounts vary by soil, but in this type of record heat, the danger of the roots being too wet for too long is greatly reduced.

In the future, it is a good idea to look at the weather forecast for the weeks following the planting time, and delay the task if at all possible if these types of conditions are predicted.

You'll need to water everyday while it's this hot. They need to grow a bigger root system to survive. You also may need to put some sort of shade over them during the worst sun of the day. Remember, they're just babies.