Broadcasters are asking for MPEG3 and MP4 and H264 video formats for broadcast. I’ve yet to find anyone in broadcast who considers ProRes a broadcast format. Of the stations I’ve worked with and for over the years, none would know what to do with a ProRes file and reject it. Personally, I”d do this in Resolve. Until Apple includes a proper, professional Audio Mixer with buses and realistic output control, I’ll never fully accept it as a professional level NLE. It’s too isolated and dumbed down.
Anyway, get the specs sheet from the specific broadcaster. All TV stations have one. Deliver strictly according to it.
As for splitting up all your audio, you’ll be using Roles as explained. Then on output, you can control what gets included and what doesn’t. FCP is actually (as stated) the worst NLE for doing audio work inside of. But basically, you’ll assign Roles for each audio channel needed for output. Then in the Inspector, configure your channels for each clip as needed. Then in the export window, configure the Roles as you need.