I appreciate you having to be very cautious with mould, and I know from expeience the spores are very hard to completely eliminate but I reckon if that got taken apart completely (as in the bridge removed, tuners taken out and stripped etc.), each bit cleaned with the appropriate product and then reassembled you wouldn't have a problem. A decent luthier will be able to do that and as long as the dampness hasn't warped anything you'll be able to keep a bass you love.