Consoles already have their rulesets posted 
Not offering any assistance in forming teams at the LAN is a huge mistake. When they sign in at the front desk they should be asked if they’re on a team or if they need to be matched up with one. This takes 5 minutes at most and shouldn’t be a problem. Leaving players on their own is going to be a major problem with TF2, you can’t hope to cash in on the freeness of the game if new players aren’t allowed to play it because they’re new.
For Halo I recommend a format similar to current-day CEVO. There were very few tournaments back when it was popular but if you need help creating a ruleset I can give some pointers, I played the game religiously for a number of years. You need to decide if you want to go CTF with 5 man teams or team slayer with 2-4 man teams. I would recommend CTF with minimal vehicles due to the level of team coordination required but that’s just me.
Also, at the last 2 LANs you’ve had dedicated servers running for TF2 and didn’t use them. If I put the dedicated servers up again, will you use them?