Oops, sorry, you're correct. I had flipped the issue backwards in the process of typing the response
You might be able to remove the faulty jack, though not sure if you'll be able to 1) find a like-for-like replacement component, and 2) solder it on the MLB without damaging it or other components (not doubting your soldering skills, but solder points on these boards are very close together, making it necessary to use a precision, low-power solder tip so as not to damage nearby components).
If you want to try something like that, your best bet is probably to go to Ebay or Craigslist to find a non-functional MacBook (preferably something with like a broken screen, and avoid one that has had liquid damage), and try to remove the jack from it, perhaps using other connectors (USB, microphone, etc) as practice first. It might be possible to just buy the component, though with buying a whole board you also get to practice the whole process before doing it on a working computer.
When all is said and done, however, you may have spent a lot more than a set of portable speakers would cost...
Hope this helps, sorry for the grim tone of the post
Attempting to solder anything on a modern logic board with normal soldering irons will destroy the board. Components these days are soldered with very local heating by vibrating tips. These are not normally hand-held either - they're part of a toolset.