I don’t see how streams coming from something that’s not OBS, XSplit or one of the other apps might “not show up”.
A RTMP stream is a RTMP stream, no matter from what program it actually originates or how it’s created, and if the incoming RTMP stream is valid enough to trigger the actual channel to go live, it should show up on the API as such.
This sounds either like a cache issue (streams DO take a while till they show up) or your criteria don’t match something that’s set differently, like stream titles for example (as I have no idea what your “criteria” are, I can’t give a better example).