There are in the vicinity of 2000 varieties of Colocasia esculenta, so there can be a bit of variation on their requirements and characteristics. Some send out runners, and some produce 'pups' off the main tuber. Water requirements can vary too, but none of them like it dry. Organic matter (compost) is better than chemical fertiliser.

If you try them in pots as you're planning you'll get an idea of how they are at spreading. That'll give you an idea as to whether it's safe to 'unleash' them or not.

Walking through a car lot in January, I noticed a bunch of taro plants coming up through the gravel. The salesman said the lot used to be a taro patch; they had survived grading, tamping, graveling, and cars driving over them.

I got a great tall taro at a rummage sale in a tiny pot; repotted in a big pot. It escaped (sent out runners) within 6 months and is turning up all over my yard.

They shouldn't be that aggressive in California.