As small plants they'd be better in bright light but shade at first. Their soil should have a lot of well decomposed organic matter. Colocasias, as a rule, take better to a lot of water than Alocasia. There are exceptions but many Colocasia grow satnding in water, not so many Alocasia will. And there are some Alocasia that will rot immediately if in wet soil. So best to be cautious, they'll all be okay if always kept moist in fast draining soil.

Growing anything next to bananas can be a problem. They're so greedy they suck everything out of the soil around them. A lot of plants don't do very well too close to them. When you first get your new plants let them gain a bit of strength in pots, no competition from other plant roots. Even keeping them in pots until next year.

Thanks much for this advice, I am keeping them in pots as you suggested. They are on in poor shape, box arrived all squeeshed and I am requesting a replacement to be sent. They are also so small there is no point in putting them in the ground.

They do bounce back quite well if you keep them warm, moist and in good light. Next year you won't recognise them as the same plants. Good luck.

I don't know if your local Home Depot sells them, check them out. I bought a black leaf online, it was minuscule. Got a back leaf gallon from HD for about the same price it was a much larger plant. HD doesn't have a big variety though.

Some agressive Colocasia grow between my bananas very much on their own. They like the shade and high humidity there and pop up all over the place. The bananas and Colocasia are growing just fine, probably too well, in sandy soil. They love water, but I would be super careful about excess fertilizer unless they die back to the dirt every year. I have to clear out banana stalks and Colocasia pretty much every week during the summer or they will invade everything.

Colacasia "Coal Miner" grows real well for me in costal NJ, I just pot up the pups before frost and over winter in an unheated attached garage.

It is rated hardy to zone 7A, my zone, but the first time I tried to over winter it in the ground was last year; it did not survive the brutal winter and fatal
late freeze/ ice.

My crinum Sangria did survive though, by off set growth, it is rated for 7A but it had a few years in the ground before last winter.

Here is a link that might be useful: Plant Delights Colocasia Coal Miner

I did not see any colocasias at HD, only Basjoos, I did buy a Colocasia Diamond Head (Large size) locally but few days after planting its dropping