Gods In Temples

Did the Greeks ever have representations of Deities in temples other than their own? For example, a temple of Apollo with also a statue or depiction of Artemis or Asclepius?

Did the Greeks ever have representations of Deities in temples other than their own? For example, a temple of Apollo with also a statue or depiction of Artemis or Asclepius?

Most definitely! 

Actually, all but the very smallest and simplest of temples would have had several additional smaller shrines within, usually, as you asked, of deities that are in some way associated with the primary deity to which the temple was dedicated. 

A good visual for this would be the Temple of Venus in Rome, which is unique in still having a substantial portion of the rear and side walls of its original cella (the shrine hall) intact (although the rest of the building is long gone.

You can see the large half-dome apse at the rear, where the large, primary image of Venus would have stood, as well as a series of niches along the side walls that once housed additional shrines to other deities.

Here you can see the ruins as they are today:


And here is a computer restoration of closer to how it would have looked in life (although the image shows a Parthenon-style image of Pallas where there would have been, in reality, an image of Venus):