I could see him signing a long-term deal, he'll be 27 in April, so a 6-8 year deal will likely be the rest of his career.
Money will be the biggest question in contract negotiations. If long-term stability and comfort are Laine's top priorities, I think taking a pay cut (relevant to the FA market) to stay in Montreal could be a option for him. Stability will likely mean trade protection though.
Now that he's finally back on track and seemingly comfortable, I don't see him signing short-term to chase the money and deal with the uncertainly that comes with it, personally. He's already been bounced around, and it didn't go well for him.