Using a much heavier rear tyre than in the front
There is no need to have equal tires on both wheels, except for aesthetics.

Just make sure that front tire has enough grip so you can remain in control.

As for getting pinch flats - make sure you mount tubes correctly and they are not trapped between tire and rim. Having high pressure should help you avoid pinches. More durable tire will help with punctures, not with pinch flats.

P.S. My own experience is limited to MTB XC marathons.