I feel like people are placing the timing of this in relation to Murray having just gone to the Vikings, but that's totally off base IMO.
The event that really mattered in the timing of this is the Seahawks signing Eddie Lacy. Once they did that, they don't need and can't afford Lynch if he does unretire, allowing for the Raiders to start fishing around.
IMO it would just be spiteful and petty for the Hawks to try to demand something for him -- he literally has no value for them and if he comes out of retirement they'd just have to cut him anyway.
I can see the Raiders giving the Hawks a 7th or something purely as a tip of the cap, but more than that doesn't make sense to me.
As for the PFT story above, an announcer hinting that he knows something doesn't move me too much.
Not letting a player they can't use anymore go home for a year or two would just make the Seahawks look petty. Trying to bring a tampering grievance against the Raiders over a player they can't use anymore would be beyond petty.
Also, people trying to read into Lynch being spotted in Raiders gear don't know much about Lynch. He spent his entire career in Seattle decked out in A's and Warriors gear. He just wasn't walking around in Raiders gear while on the Hawks out of respect for his team. I guarantee the day after he retired he dusted off his Raiders hat. For him it's about representing Oakland, not trying to send secret messages about how he's going to play for the Raiders.