I had an idea to do something similar before. My goal was to be able to swap guitar pedal order digitally.
I think you may have a good combination, however the max4549 is a triple 3x2 setup, which may be overkill depending on how many things you have hooked up. Converting the audio signal to digital before the crosspoint switch, and then back to analog afterwards sounds doable. I haven't tried it though, as I abandoned my idea(my pedals decided they only liked a specific order).
I'd say one thing to be sure of is most chips won't like a negative AC voltage, and a guitar (pedal) can sometimes have a swing > 0.3 to 0.3v. Just bias the signal to bring it into a positive area to work with. The datasheet for the max4549 says it has internal voltage dividers for a bias.
Your ADC/DAC combo has a different input and output quality, but both are more than enough to achieve good audio quality. Depending on the signal you are throwing through this, you may only require something much lower quality. Unless you can find the chip for cheap, and find a DIP version or can solder SMD chips well, reconsidering is also an option.
Some things to consider. Good luck!
p.s. you can type [ url ] (your url here) [ /url ] but without the spaces in the "[]" areas, to give a hyperlink to the webpage, or click the 2nd row, 3rd from the left button (under the underline button), rather than having to copy/paste to open it.