Regarding the headphone:
If my memory serves me correct, there are different plug standards (CTIA / OMTP).
And FP2 is supporting the CTIA standard.
If that should be the reason for the headset not working, an adaptor might help.
You might have a look at this thread/posting:
I have no idea, what standard your JBL-headset is supporting, but maybe your manual will have some info on it; or you could ask JBL support?
As a small consolation, you were awarded the well deserved badges for 3 / 4 / 5 years Fairphone 2.