Did you buy the board from ifixit? I have the same issue regarding audio (no audio device found), in addition to the usb port not working.
Just followed this guide to replace a burnt out/corroded power socket. I bought the part from this site. Now the power is fixed, but the USB socket does not seem to mount anything, as in it doesn't work. I have not tested the headphone port. An interesting observation: the first time I turned my macbook back on using battery power it said battery not available. I turned it off and on again and this resolved the issue.
Does anyone have any ideas about the USB port not working? Have I bought a faulty I/O board from IFixit?