60F is right on the edge of what bananas will be able to grow in. Are you sure you can't get the temperature to 65F during the non-winter months?

Especially for very young bananas, they are much more sensitive to temperature.

Here, you might see this: https://www.youtube.com/watch?v=nhJloTO6VS8

I would recommend keeping them potted and in the house for their first winter. Either dwarf or tall it will still take a number of years to get it to fruit. Lighting and warmth being key. With it almost being March your gh should be getting close to 80F in the day which is what they like.