Wow, those puppies are all doing great guys.
One comment on mulching Colocasia. If you look at the way new tuber is added with the current seasons growth, you'll notice that roots form on the added tuber. For this reason I remove bark type mulches out to a few feet from the main shoot. I mound compost or a soil compost mix for these new roots. In these pics you can see that these new roots will be forming at or above the soil level of the original planting. The Kohina may be only an inch or two below the soil level.
..with Hawaiian names for the parts