Brown, Tierney, and Duclair are all fine to stay medium or long-term on reasonable deals.
Duclair is obviously pretty "boom-bust". If he can recapture any of the promise of his early career or the first 1/2 of his Ottawa season, he's a solid top-6 forward on a team with very few of them. He has to know this is the best opportunity for him. Even if a longish term deal at a discount is better than the alternatives. Every NHL player is one bad hit from losing their career. Yeah, I'm sure he'd prefer to be a UFA with a few more 20 goal season to cash-in, but the alternative is that he gets injured or never finds another good stretch of play to earn big money. Ottawa obviously doesn't want to give him term, but I think they should consider it at the right AAV if the coach/trainers are comfortable. Locking up a guy who can score 30 goals to a good deal with both term and dollars is every GM's dream. Especially one on a budget. Maybe he wants to "bet on himself", and I'm sure Ottawa will oblige him, but we can't be scared of retaining him either, we simply don't have the forward depth to keep shedding players.
Brown and Tierney meanwhile aren't amazing, but they're solid NHL players who can play in the top-9. Nothing special, and ideally you'd have them on your third line or as complementary pieces to better players, but as long as the term and AAV make sense they're good pieces because they can still produce with 3rd line minutes and limited line-mates.