I think neither are realistic.

The only realistic Hagelin trade is adding a pick for a team to take his contract.

Let's see, Hagelin. 2 goals, 6 points makes 4m and the his team stuck with him next year too. Duclair, 7 goals, 13 points, making less than 1m. What do you think Arizona does? They would be better just to not resign Duclair next summer then to take Hagelin.
I just don't think the Leafs can afford the cap hit of Letang, although your trade offer is OK. (Pens fans would want more undoubtedly). Leafs would prefer to find Dman help with any available free cap space rather than the 7.25m long term cap hit of Letang.

Thanks for your opinions what changes would you guys make

Changes I would make. I can't see any team wanting Hagelin. The only way possible if the Pens would take back equally bad money for an equally non performing player. But what would be the point then?
There might be a team willing to take Letang, but I can't think of one either. He's good when he plays but his injury history makes him doubtful that any team would trade "equal playing value" for him. His most value to a team is probably the Pens. He stays, I think.
And a little side note. The playoff race in the Eastern Conference is close, I can't see any Eastern Conference wanting to help the Pens with players or their cap.