If an instrumentalist or drummer or singer is a full-time staff of the church; and employee of the church; such a person must be paid. It is just like working in a bank. The church is his or her office, so such a person must be paid.
It is wrong to ask for payment when you are a member of a church and still get your source of livelihood elsewhere. You cannot be working in the bank, a company etc, and still tell your pastor to pay you because you are a drummer, instrumentalist, etc. Does it mean you cannot help God’s house without being paid?