Visa appointment date may be up to six months before the visa start date
Musical instruments are treated as personal effects so you can take one or more with you without worrying about customs procedures.
If travelling by plane be aware that tuning forks may be considered a potential weapon so maybe place it in the hold luggage!
One puzzle at the moment concerns taking your instrument into Europe if it contains products that are protected under CITES (for instance because many instruments are made of many different genuses of rare woods such as genuses of African Blackwood /Rosewoods). There is more information on this Facebook page here.