So I have a Wolfson WM8741 DAC with balanced outputs (2.5v offset and swings really close to the rails and has a max load of 2k) which uses a digital volume control so there is no pot in the signal path. Right now the system uses an op-amp and is cap coupled for the output. I would like to change this to get rid of the op-amp and caps in the audio path.

What do you recommend for a coupling 1:1 transformer?

For a 1:1 transformer I would suggest a PCW10K/10K, WSM10K/10K or a XSM10K/10K. Any of theses should work just fine.