No. It is not 'ideal'.

I'll take discs front AND rear every time. True that the front has the most stopping power. But in technical situations, especially downhill and with loose trail surfaces, the rear is the one that gets more constant/sustained use- the front often has to be feathered or not even used at times or you will lose control. Being better at stopping power than a v-brake, a disc in the rear will always be a more effective partner to a disc in the front. Just my own opinion.

But, to answer the OP, disc front and V rear will probably work just fine. I have not personally done it, but I'm gonna guess that a mechanical disc (vs. hydro) in front would be the best choice in terms of more closely matching the modulation characteristics of V's and discs.