I wouldn't overthink this honestly. Yes, they did this analysis because that's their job, and they often do such things to apply a price tag for what the "value" they will get on the return. They are also constantly doing this. They are constantly looking at the value in the market, value on their team, and comparing the two for the purposes of getting better value and better production. It's one of the real issues with baseball, honestly, that teams are looking to get better value and sometimes not sticking with the better player.
What do I mean by that? Well, teams are more likely to be thrilled with a 3.0 WAR player for the minimum than a 4.5 WAR player for $8 million because of the value play. Now, some of that is necessary to maximize a roster, but some of it is also limiting because a 3.0 WAR player is not the same talent as a 4.5 WAR. Does that make sense?
With Wong, it is, as you suggest, more simple because the situation is. They needed to cut cost, and they could with his contract and with Edman on hand at his salary. There is another element to this that gets back to your analysis. They are also playing the market. They clearly think it's going to be depressed and that market factors are going to make it possible to sign a replacement, re-sign Wong, or spent less dollars elsewhere on a player that has a salary that is shaped by the current market. Again, value. But that's the strategy in play.