I think that would probably be a fair trade. Laich's contract value is worse in terms of amount and value for the player. He's 32 and that's right around the time guys like him fall off a cliff performance wise. Maybe even a year or after that, judging by his stats. Just goes to show you how most average NHL forwards really peak earlier than perceived wisdom used to indicate. By the time a guy like Laich is 27/28, his best seasons are likely behind him. But he's only got this year left on the contract.
Fayne's is less money, and he's 4 years younger so could well bounce back in a shutdown role (and D tend to peak and fall off a year or two later than forwards), but he's got another year after this season that could be concerning if he doesn't bounce back. He's been pretty awful this year, in all honesty. His only claim to fame was being a good "shutdown" guy. He's not physical, he's not good with the puck, and he has zero offensive ability. This year he's looked too slow to be able to keep up with the pace, so he's not even capable of being a shutdown D anymore either. If I were a GM looking at trading for him, I'd be pretty nervous that he's just too slow to play in the NHL now.