Some rules need to be put into play since the rules are being so specific.
1: Is pausing on for this tournament?
2: How are you deciding who gets to play on which port?
3: How are you deciding who picks the random stage to be stroke first/last?
4: Is the normal sound going to be dead center or on music or on sound?
5: Up to who's discretion is this at... just the rules?
My solutions:
1: OFF
2: Rock/paper/scissors Bo3
3: Port priority (1st port picks the random stage to be stroke first)
4: Sound is going to be on dead center of sound/music >_>
5: It's at your/the other TO's discretion.
Just some tips from a fellow TO and a person that's a stickler on rules in case anything gay arises (and it does trust me).
Also, I'll look up the counterpick-able stages that are ON for this tournament based on what you said in the OP and I'll make a separate post when I don't have work in 6 hours lol.... or someone can look that up... that'd be great haha.
Hope this helps! :D