I think that there might be a difference as to importance between road and trail bike since one is generally steering a MTB more than a roadie. I can only speak for road bikes since that is what I primarily ride.

Over the 35 years that I've had my Fuji, I have found that I wear out rear tires twice as fast as front tires for whatever reason, so in the OPs case I say the rear tire should be replaced first. Flats seem to happen in a similar ratio, usually from tire cord wire rather than glass or sidewall bruises. Very rarely do I have a for-real blowout - maybe four or five in 35 years and only once on the front - so that 'front tire catastrophic failure' does not weigh heavily on my mind.