Just to ask, do ALL Runs need to be streamed over Twitch or can they be streamed on YouTube?

Both are fine. You dont even have to stream the run. Just as long as you have a recording of it. So even a Youtube video would work. The main things you need are the recording itself and a timer.

Awesome, can the timer be edited in after the recording or will I need to have that running during the recording?

Yeah, it can be edited in post. You'll likely wanna run a timer locally anyways (for comparing during the run), so double check the final time there with the final time in the edited timer just to be sure your video isn't missing chunks.