answer to both you questions with confidence
just checked...the LO is giving a very fine 122.88 Mhz sine wave
and please read the following documentation....you can clearly find the answer to your question
http://wiki.analog.com/resources/eval/user-guides/ad-fmcomms1-ebz/hardware/functional_overview
you can read in the transmit section...
the DAC translates the baseband frequency and interpolates it according to the interpolation factor