Can anyone help with a tree frog inadvertently brought in for the winter

[MN Tomato]

Hi, this is neither technically terrarium nor orchid,* but from looking at your fabulous setups I know some of you have experience with frogs indoors.

Despite my best efforts in the fall to gently evict the fauna living in and round our large potted plants before they came inside in the fall, it seems a tree frog managed to come inside, and I wonder if anyone has any tips so that I can help it get through the Minnesota winter indoors.

Although I have not seen it, I have heard it calling the last two weeks. It is a grey tree frog (Hyla versicolor), because that is what hangs around our house, and that is their call.

It is inside a large staghorn fern ball that has a sort of hollow in the center that collects fallen leaves and things (the fern ball is in a wire basket propped over a tub for drainage). I don't remember when I brought the fern in this year, but it was before THanksgiving at least. I dunked all the large plants and pots fully into a tub of water for 20 minutes, which usually flushes all the critters out, but I guess it didn't work this time. The temperature in the room is a pretty steady 65-68 degrees, so it has probably not been hibernating, but I haven't seen any poop around (we are used to seeing it on the deck under the outside light) so it seems not to have ventured out. The humidity can get pretty low, down to 30% when it's very cold outside, so maybe that is why it is staying inside the more damp fern ball.

How can I help it to survive the winter? It will be at least March until it is warm enough to let out -- that's usually when we hear the frogs start singing.

The only bugs around in the house are a few fungus gnats and some box elder bugs, which are mostly dried up by now. I went to Petsmart and after consultation with the nice folks there, bought a dozen "crickets, small" and dropped four of them in. I'm not sure how I will know if it works, but hopefully at least the crickets (and the frog) will not be inclined to wander too far.

So my questions: Was that a really bad idea? How do I keep the rest of the crickets? How many crickets do they need to eat? Do you think it would eat bait/compost worms (Esenia fetida)? I could get some of those.

Thank you in advance for your help.

*I can post a picture which includes a cymbidium plant so it is technically "orchid-adjacent."
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