Hi, Lauren. Refinishing a piano is no different than refinishing any other piece of furniture, with two big differences. The first is that you have to protect the mechanism (keys, pedals, etc)from the refinishing process. The second is that the size and shape don't lend themselves to brush finishing. You really need an air spray gun(and a suitable place to do the work) on a piece as big as a piano.
I would think that your first job would be to contact a piano tuner and have him look over the mechanism. Be sure that the action, hammers and felts and so on are worth restoring to playable condition. If they are, then he should be able to direct you to someone that can do the refinishing. If they are not and it can't be made playable, then you can decide if you want to refinish it yourself since it will just be a decorative piece or send it out. The piano tuner/repairman might be able to give you some direction on how to find its history.
Chemical strippers do not change the color of the wood or the stain color. There are some seeming exceptions with some modern finishes where the color that you see is in the finish but that would not apply in this case.