I think experience plays the biggest part in avoiding/dealing with capsize situations. The more you sail a boat, the more you will be in tune with how the boat reacts to wind, waves, trim, etc. Violent capsizes on a cat (pitchpole) are the result of the hull(s) being forced underwater while the sails continue to accelerate. This happens in breezier conditions (12-15+ kts.), can happen upwind or downwind and is caused by hitting a wave and/or catching a wind puff. Time on the tiller will teach you how to steer through waves, react to puffs and recognize puffs on the water (you may know this from your monohull experience). "Non-violent" capsizes are typically the result of trying to fly a hull and letting the boat go a little too far.

I don't have too much experience on the TheMightyHobie18. I would think the longer length and higher volume hulls would make it much less prone to pitchpole/capsize. It definately has a higher crew carrying capacity but is also bigger and heavier. The H16 has a reputation for pitchpoling. This is overstated a bit by other cat sailors (much as monohull sailors overstate all catamarans' tendency to capsize) and can be contolled by depowering, weight placement and all the other things experience teaches.

It's hard to go wrong with a H16 or TheMightyHobie18 as a catamaran for the family.