Yeah ^, Have 1 layer as your switcher with various inputs, then above that layer have your normal comp. Use Video Router specified to the first layer and then add your FX on that. Change source layer if something is wrong.

You can assign each deck a DMX address just like you do with MIDI, or for use with a single address or encoder would to be to map the |< >| buttons next to the deck with a DMX address, then assign your deck UI in your console to that specific address.

Directly, No.
However you can send out OSC or DMX from Arena and then use a free translator app like Chataigne to convert to other protocols.

Correct. Currently Resolume can only do a stereo out. You can kind of bandaid it together using Resolume for mapping and video playback and then have Ableton or some other DAW send out audio. You can send another audio out track from your DAW to Resolume sending out LTC so that the video can follow ...

Good luck going through life with that type of attitude.

With Python I usually do something like:

str("xxx") with xxx being the int(operator)

You don't lol. They guys are reworking the audio system for multi channel out but there is no timeline. Could be next month (haha) or could be 10 years? If I was to guess... Maybe a year or two??

I work pretty heavily in the corporate world as well. Most the time they don't need the last 30 sec, just something that shows the end, it could be 5-10 sec and they're happy.

Just have companion send a float value of 0.9 to
/composition/selectedclip/transport/position

Anytime
There's a ton of documentation out there for it.

It's just a float value. In Wire you can get get media player clip duration and remap 0-1 that way but for non wire functions you would need to ping the clip via osc with a ? to get the duration and then do a remap externally that way. No in the box solution that I'm aware of atm.