Please excuse the venting that follows, I just need to get this out...!! As I was tearing down the machine to get the...

I got the jack from iFixit today, carefully resassembled and everything is working, including that speaker connector. Sure enough, the loose wires stayed on there and everything is working perfectly. As long as the customer doesn't come back next week and complain that the speaker is busted, I'll be elated. Thanks for the answers (and a big thank you to iFixit for all of the assistance over the years with the repair guides).