I am familiar I helped run an entire student radio station at one point. Governed by OFCOM and have helped run said station both online and of the FM bandwidth. Which also won student station of the year. So I am in fact familiar.
As per the TOS and ROC of Twitch, Streamers need and should take resonable steps to prevent certain types of content on their shows, which includes and is not limited to, someone coming into a voice room on a game and dropping all the swears. Having a fixed format show, with call in such as this runs the risk of that, which means vetting the pre-records or listening to them offstream before hand. Which doesn’t lend itself to such pre-records being collected an delivered via Twitch Extension (optimally speaking). Thats before we consider file sizing and upload limitations. Since you can’t live record a mic, since you can’t prompt for mic permissions from an extension
Currently I would expect twitch to reject an extension that accepts file uploads. Also the architure of a twitch extension would make it sub optimal to accept such an upload since you’d be talking cross domain for a start.
For such a call show it would be optimally better to collect recordings (and vet them) before the show, or doing it offsite, where people could submit a video recording instead, (thats been uploaded to a suitable delivery mechanism such as youtube) and include those recordings on the show instead, which potentially works better for a live stream where it’s about video more than audio, compared to “pure radio”.
Or as has been done in the past with such shows, literally getting the person on the show via Skype or Discord or google hangouts or other video/voice application.
Further more past involves or myself on other shows of this nature on Twitch, you need to start collecting call in content weeks before the show, as a lot of people don’t submit, or turn up to the show and go “oh shit I could of submitted but I didn’t know this was on” and at that point you just haul that user on the show live rather than prerecorded.
The architecture of extensions and the format of shows on Twitch is generally against this sort of format. Based on my knowledge of radio, live streams, building these things and actually watching some of this type of show and participating in them myself