I will not put sempervivums there just because most will just die in the blazing heat since they are more of alpine succulents..maybe some echeverias or haworthias or sedums may take it. Hopefully the shade from the birdbath will help the plants. If you are going to put water on the birdbath all summer long, that would certainly help cool down the succulents.
We get triple digit dry heat here too, and shade really helps sustain the succulents, but even then, I still suffer some loses along the way just because of the excessive heat.
