I apologize for the delays, RL got a bit crazy with real estate stuff and work stuff, and then driving 10 hours today for work did not help my online availability.
I'll do my best to try and answer all questions now, and will extend the SEC choice 24 hours (new deadline being 24hours before deckbuilding deadline) for this round to hopefully allow enough time for better decision making.
how does discard/salvage work with the SEC?
Salvage like normal. you can salvage any of the cards from the deck whether SEC cards or not.
You can't discard SEC cards though, as they are not in your vault. If this causes you to have less than 15 non-ppm cards in your deck, the remaining go to vault discards as per usual rules in section 4.3.
The example makes EC even more confusing. Maybe a better example with detailed pick(s) a team (has to) make and the result of it?
I'm not sure if
dawn's example helped, but if not I'll attempt another one here:
Hopefully that clarifies it better. but if not, I can try again.
So... what was the prize?
We are awarding 1 free set of salvage(6 cards) from the WarMasters vault(we have 12+ of every card).
Currently the points from this appear to be:
: 2+3+2=7
: 1+2+4=7
: 2+1+4=7
: 2+1+2=5
: 2+1+2=5
: 1+2+2=5
Since we have a tie for most points, we will split the winnings among the 3 teams. Each time, darkness, and earth will receive 2 free salvage."All decks may contain up to 2 additional copies of the card regardless of vault amount."
All decks like not just our decks, but every Teams's decks?
Originally our intent was just the team who stated said card could use the extra copies among their 3 or 4 decks. But after discussion with asdw, we agreed that we will open it up to usage for all 6 teams to try and elevate the strategic play and mindgames that this could bring.
Similar to past SECs we are willing to adjust the card for the 2nd and 3rd round usage if there is enough negative/constructive feedback regarding being unbalanced. But we currently feel that both options are fairly balanced in their own way just bringing different strategic elements to play.
12 hours 39 minutes remaining, and no official answer for SEC, how the hell should we decide? 
Additional question: let's say 3 teams choose Soul Catcher. That would mean +6 copies for each team?
Nope, these are only partially stackable for multiples. Each additional choice will only add 1 extra card instead of 2. If 3 of the teams choose Soul Catcher, a total of 4(2+1+1) additional Soul Catchers may be added to each deck.
Edgecases:
I have 14 discardable cards in a deck, 2 of which are Soul Catchers. SEC card is Soul Catcher. I have 2 Soul Catchers in vault. If the deck loses, do I discard 12 from deck & 12 from vault? Or do I have to discard my Soul Catchers?
Alternatively, same situation, but 17 discardable cards in deck. Am I able to discard Soul Catchers as deck discards?
SEC cards are not in the vault, and thus cannot be discarded. So in your example, the soul catchers from your vault would be the ones being discarded. and if this causes you to fall below the required 15 deck discards, you will follow the regular rules per discarding in rule 4.3.
Same ruling for the other situation, if a soul catcher is added to the deck from the SEC it cannot be discard in any form(vault discard or deck discard).
If you have any amount of soul catchers in your vault, decks will use all of those first before attempting to add in the SEC additions. After the vault has run out of your soul catchers, then the SEC additions will count in.
