For the love of baby jesus, do NOT make me use a damn dongle to plug in my headphones.
I have the answer.
They will make cases that have the dongle built in, so that you just plug in your headphones
as you normally would.
The case may have to be a little larger to include the dongle but
I bet it will be fine.
That's the only way I'll be getting an iPhone 7, no dongles no bluetooth headsets for me.