This is a tricky situation, and I'm sorry you've ended up here. This is probably not what you want to hear, but I would not hold a dance with recorded music. Instead I'd:

1. Have musicians play acoustically and accept that it won't be as loud as you'd like. Until a hundred years ago this was the default. [EDIT: This could be an opportunity to gather a giant open band!]

2. Get a crash course in running sound. While it's a complex job in its entirety, if you're just trying to make a few instruments and a caller a bit louder there are simple options that are not difficult. Depending on what equipment is available you can plug a microphone right into a speaker, and just turn it up or down until it sounds right. If you wanted to do a virtual training session I could do 9pm tonight or tomorrow night.

3. Reschedule the dance. If you're worried about losing money I could chip in a bit.

All of these have downsides, some of them big, but overall I think it's very important that contra dance goes to live music.

As a practical matter, if you do use recorded music make sure you listen through it while tracking sections to make sure it's square. I'm pretty sure there's at least one track on the Kingfisher album where we edited it in a way that means it won't work for dancing, and same goes for the Free Raisins album.