I don't live in your area, but I grow dwarf bananas in Hawaii. Maybe I can help. Mine get chicken manure, compost, horse manure and grass clipping mulch. Most of all, they like lots of water and lots of sun.
A friend told me to limit the number of plants in each clump to 5 or so so they don't get too crowded and compete with each other.
To keep the birds from eating the ripening bananas, I put netting over them.
Awesome! I have a friend with chooks & another friend who has horses. I'm not sure as I can afford more than 1 plant, let alone 5 but I will bear that in mind. Everyone here seems to pick the bananas when they're green & lets them ripen like that. Altho' I've always thought tree ripened fruit was the way to go. Something about the polysaccharides (sp? ) in it vs non tree ripened fruit.
You don't need to buy more than one plant. They'll send up shoots and start new ones on their own! You might even be lucky enough to find someone who has bananas and is willing to give you a starter plant.
It's easier to just let them ripen on the plant unless you have critters who will eat them before you do!