Instruments:   Lots of 19th C. local dances hired itinerant fiddle players - earlier accounts say the musicians who also played in churches would play for dances. This would have been things like fiddle, cello, maybe flutes, oboes, brass etc. early 20th century you get concertinas and gradually other squeezeboxes. Musicians tend to use a) what they have on hand and or b) what suits the musc plus c) what's loud enough. Hence the post Pat Shaw use of the full-sized wet-tuned piano accordion (run away!)
K