The qualifying offers deadline is 7/15 for those players the Islanders tendered an offer on 6/29 which retains their NHL rights (Johan Sundstrom signing in Europe) regardless of whether it's accepted by the player or not.
Long story short if Brock Nelson, Kevin Poulin, Kevin Czuczman, Mike Halmo accept the offer they have a signed contract for 2015-16.
If not it becomes a negotiation, the players are only free to sign in Europe/KHL or stay home.
For the Bridgeport players 7/14 is more like 8/14 in the European leagues because they start sooner, all of them could have signed with another team since the end of last season.