PA zone 5b or sixish

I have some ornamental banana trees that I stored in the basement over the
winter. One seems to have fared well losing it's main shoot and sprouting
several new ones in contrast to the worst one which I finally chopped off
it's shoot in desperation that it was so sickly it might rot the plant.

When I grow veggie seeds I have to break the plants into real light
gradually or they turn white... do I have to do the same with banana trees?
What are the coolest nights they can tolerate?

It's been very cold and rainy the last few weeks and even had a hard freeze
several nights ago so I didn't put them out for little bits, but it is to
take a dramatic turn starting this afternoon with near 80F and tons of sun
tomorrow and mid 80's and high humidity and lots of sun after that. Should I
just put them out there and let them go or do I need to break them in (I'd
rather put them out there, but not if they'll die after nursing them all
winter)?