I'm interested in just the ADAU1761 SigmaDSP and developing with that because the board's connectors provide the expansion I need. Can it be used that way?
Yes, the EVM can be used for general SigmaDSP development with SigmaStudio. A clock must be provided to the ADAU1761 and there are two easy ways to do that. Details are in the board manual and there's a quick summary on the Documents Wiki.