The cracked water pump suggests a severe overheating incident. Did that occur? If so, make sure whatever caused it is being fixed along w/the head gasket. Otherwise you’ll be right back at square one. As part of the head gasket job, might be a good idea to have one piston removed and checked that it retains the correct dimensions. If the pistons are warped, the engine will never run correctly, new head gasket or not. In that case a replacement engine might be your best option. Bad news, but better to know now than latter.
No uncommon in the pandemic era. I expect your best option is to be patient & wait for the part to arrive. Seems unlikely back-shipment on head gaskets would be longer than a couple of months. Did you ask if they’d provide a loaner in the meantime? Also, check w/your insurance company, maybe your policy provides a loaner. OP isn’t the only one w/this problem, even the Magliozzi family.