The destructibles are actually quite simple, just activate/instantiate the version in small pieces and then foreach(shard in shards){
shard.AddExplosiveForce(<appropriate strength and distance>). They go ballistic like that, because some of the colliders overlap, which introduces a certian amount of chaos and upward motion.
Additionally, having some that break easier than others adds a bit of variety to an otherwise small set of destructible objects.
I really enjoyed placing them, tho! Glad you liked it!