Get a $15 multimeter (auto part stores, Walmart, etc), and check what is the impedance of disconnected speakers. Cut the wires between other speakers as well, and check their impedance as well. I doubt all were connected in parallel.
As for how it will sound - who knows... The enclosure does not seem to be acoustically isolated, so I would say these were PA-style speakers, not "Hi-Fi". As for amp - places like PartsExpress and Amazon sell a lot of under-$50 amps for one to play with.