Nice homer post. If the Cardinals storm back and take the Central or even nab the wild card, Holliday/Beltran are going to get some consideration. You cannot simply write them off at this point.
I think you can definitely write Beltran off at this point and I would be inclined to think you could do the same for Holliday.
With Beltran's .276 BA, in order for consideration, he'd need to be above and beyond Cutch and Braun in the production numbers, which he is not. Plus he has fewer than half the number of WAR than Cutch and Braun at 6.3 with only 3.1.
As for Holliday, if you're considering 3 outfielders, and one of them doesn't steal bases while the other two do, I think the same thing goes for Holliday as Beltran except SB instead of average. In order for him to be considered with Cutch and Braun, he'd need to have huge HR/RBI/R totals in lieu of not stealing bases, but he doesn't. And Holliday is almost 2 wins fewer in WAR.
Posey should most definitely be in the conversation. A catcher with that kind of production is more valuable than any OF like Braun and Cutch to a team, and I also think that the Giants are more likely to make the playoffs than the Bucco's at this point.