What would be the best part solution for a lock-in amplifier to get the sin / cos for the multiplier and drive clock (in phase with sin) to excite the sensor. Would it be 2 x AD8934 ?
Is it possible to do it with a single DDS ?
I presume you are only of the frequency range that the DDS can facilitate. There are a lot of DDS that can support frequencies of 1-10MHz. However, if you are looking for a way to make the board with few components, I suggest to us AD9958 which is a 2 channel DDS and can support beyond 1- 10MHz of CW frequency.