Timescale depends on how long it takes to reach the minimum order quantity, fabrication will take a month after the orders are recieved. The heel can't been pre-drilled because the location of the holes depend very much on where the holes in the body are located and different basses may have holes that are out by a fraction of a millimetre - which matters when it comes to the neck. However, inserts and neck bolts will be included.
Drilling the holes is relatively straight forward if you have brad pointed drill bits, clamps and a drill press. Just install the neck in the body pocket, make sure it's a good fit against the longer side of the neck pocket and mark the holes by putting a drill bit or something pointy and the same diameter as the holes. Then just twist so the end makes a mark in the heel and then transfer the neck to a drill press, clamp it securely and drill out the mark with a brad pointed drill bit that almost matches the diameter of the inserts. Then screw the inserts until flush, add a blob of superglue to each and install the neck in the body.