Terry won't be playing center in the NHL. He's a better RW. Also, Max Jones will be on the team as well. No reason to sign Chiasson or Lee.
The ducks want to get younger, not older. Shelling out $7 mil a year for a player who is about to be 30 in a little bit over a year is not what gets you younger.

I'm assuming that you mean Henrique shouldn't have been signed in the first place, because you just said "No Trades" lol. Even if that's the case, I still wouldn't overpay a free agent this year. The Ducks need to rebuild and buying expensive free agents before you know what your young core looks like is a recipe for disaster. It will hurt them when everyone needs raises, and it takes away a roster spot from a young player (in this case it's Sprong). Even though Chiasson is cheaper, $3M is WAY too much money to pay a 4th line winger who only scored because he played with McDavid. Shore can easily play 3rd line center if Henrique is gone, and Isac Lundestrom needs to develop into a top 9 player, not be forced on the 4th line when the Ducks have Rowney who is more than capable. I get that you're eager to see the team improve, but when you're going through a rebuild/retool you just have to bite the bullet and be patient.