Ports are a metaphor demarcation to me. That's to say the usage intentions can be both constrained or enhanced.
One also needs to consider factors of design interactions. A simple enough in concept "headphone jack" adds complexities of switching internal to external audio. Then impedance matching between internal speakers and whatever gets plugged in to the jack.Let's also consider ground loop/stray voltage issues. Even if most of these have already been solved by "prior art". Even then- safety certifications and RF compliance factors become often nasty bugbears. Look back to the " All-American-5" tube radio of transformerless design for details in how they were handled.
As for a microphone port- could an internal microphone suffice? If so- let me resurrect a techhack from long ago.
The concepts below that are not exempt as prior art, are donated to the Chumby Project under copyleft save only for my hope that someday they may earn me a Chumby incorporating them - as honorarium.
Dynamic Speakers CAN be used as MICROPHONES!
Route the audio thru some switching or path isolation stunt- Possibly even using the audio out amp as an audio IN amp. All it takes is some logic driven switching . Left open for further discussion is interactivity potential so created.