The Cantabrian gaita is, as far as I know, almost the same as the Asturian one. Nowadays there are a couple of makers who produce this type of bagpipe, which has a drone parallel to the chanter in a common stock. No reliable references about it. Supposedly sbagpipes were broadly played in Spain in the middle ages. Here is a picture of a bagpiper playing an instrument with two drones, and a picture of two bagpipers playing droneless bagpipes.
Galician bagpipes come in lots of styles.
The current gaita galega is a mouth blown beast. Some are trying to bring the bellows blown Galician bagpipe back, using an old picture as reference. This Scottish Internet Book Site owned by Nancy A. MacCorkill .