I don't know whether the GM has a plan, and I agree with a lot of your points about the vets, but I find it difficult to conceive of a plan where a player like Laughton does not fit.
See, here's the thing about Laughton--he had a very good year in a contract year. And, yes, he is a good, versatile player. In isolation, signing him is not a problem, but in the big picture it is. For years, the Flyers have lacked true impact players, and when they become available, it's the same old story with the Flyers--"we're up against the cap."
Since the salary cap was initiated, the Flyers have been obsessed with jumping the gun and signing average-to-good players to too much term or cap hit, then claim there's no money left over to add impact players. And it's convenient to say, "who cares about the 3 million or 5 years" until you want to bid on a player like Laine, Forsberg, etc. and you have 150k under the cap to maneuver. Regardless of regime, the Flyers continue to make the same mistakes, and it's nauseating. In the offseason they rushed out to re-sign Hagg and Braun--for what? Look at this team. You could have filled their spots with waiver fodder or AHL players and been just as good this season.
So, is Laughton a bad player? Of course not. But this is more "ready, shoot, aim" by the Flyers. They should be looking to completely revamp this team in the offseason--and they'll need as much flexibility as possible to do so--and they just committed 3 mil and 5 years to a bottom-6 forward who is not essential towards turning this club into a serious contender.
You address the big moves first then round-out your team with the best available options left over that fit your budget--you don't spend your budget on "okay players" then say you have no money to add star power.
In 2 years, Laughton will be the new Matt Read, and we'll have 3 years left of his deal.