I think they also said they would probably be taking things a year at a time. Daniel said after the World Championships that he really enjoyed playing on the big ice again and was no longer ruling out a return to the SEL before hanging up their professional skates for good. If that's the case then chances are they come back after next season and the longest Gillis will be able to convince them to sign for will be 2 years.
I would not be surprised if the Sedins pack it in early. The game is changing and certainly does not suit their cycle, lateral, back passing game. It's all north/south straight ahead, fight through checks. So not Sedin hockey. Not surprising they love the Big Ice European game, it's like no hitting, recreational hockey for the dipsey doodlers and cyclers.