The photos used in the opening are changed virtually every episode, in part to reflect which characters will be in that episode (though others get scattered through as well). ABC did a cast-wide photo shoot to get new(er) publicity shots for the cast, and some of the head-shots are used in the opening. In some cases they kept the head-shots they were already using, maybe because they didn't get anything better in the new shots. I'm sure this "photos dropping" sequence was designed because it is cheap and made it much easier to delete someone who is no longer on the show (fingers crossed Peter/Wes Ramsey will be removed after Feb. 22). I dislike the music they're playing as the photos "drop", though---it's more like background music for a scene and is not memorable at all.
As for the temp recasts, I guess they have the episodes mapped out and can't "shoot around" a missing actor. The temps are unexpected costs, though, and Frank V hates spending money! The temp Sasha is the real-life sister of the regular Sasha, so at least they kept it in the family.
Port Charles is experiencing a "heat wave" so I have to think maybe Victor's tinkering with papa Mikkos's old weather machine. Maybe that Ice Princess had a sister to play a temp recast, Fire Princess? Victor has turned out to be a very well-written and acted villain--not all snarling and hammy like Peter, or angry and smug like Cyrus. Victor is just....smooth. Fran would be rather shocked by Mr. Sheffield's latest shenanigans.
Many are speculating that Liz's odd occurrences (moving her ring around, the shredded wedding dress, now a card from "B") are actually manifestations of a split-personality where she did these things to herself. I think it's unrealistic but hey, Becky H deserves a story of her own, and I'm sure she would act the hell out of it. But unlike Maxie, who can just dump her three kids on any number of people, Liz can't just ignore her kids and wander off with a new identity. Jake and Aiden are too old to end up in Monica's daycare center at the Q mansion. I'm hoping the story is...well, something different. It looks like they ditched their plot idea to bring Jeff Webber back to town (probably couldn't afford a big name for the role), so this might be the consolation prize.