Would a regular 3.5mm aux headphone mix splitter work? I used to have one of these for my laptop and it did what you’re asking for
https://www.amazon.com/dp/B071DMCZQF/ref=cm_sw_r_oth_api_glt_fabc_ZXN585ZM4802Q30K5KZG Or just look for mic and headphone splitter.
Why do you need to plug in the APM at all? Most computers will allow you to selectively choose the input device (on Mac, you hold Option and click the speaker icon to see the input options). So you can use the headphones wirelessly, but still use a wired input.
If you're looking to just use a headphone jack to wire both, then yes, you'll need the official Apple Lightning to 3.5" cable, as well as a 'y' cable to combine the signal from a separate mic, like this - https://www.amazon.com/MillSO-Headphone-Splitter-Adapter-Compatible/dp/B071DMCZQF