It makes a lot more sense for games that won't be prioritized by Sony to find another partner anyway.
The fact is, with 4 big marketing deals all around the same window, Sony will likely stretch themselves a bit thin. Especially if they also want to have a profit-focused bundle with a first-party title into the mix.
It would not be strange if one or two of their co-marketing deals will probably end up getting less attention than the ones they prioritize.
That is crazy to think of, since each one of those deals could easily be a flagship marketing deal for that holiday season, same way Destiny and Battlefront were Sony's marketing darlings for their respective holiday season.
Sure, it makes sense for Ubisoft but I don't think it's controversial to say that if Sony wanted AC or SoW marketing deals, they'd have them. It's obviously not the case with all of Microsoft's marketing deals (FIFA, Madden and BF1 are/were big), just some of them that are inconveniently timed against much larger deals.
As for stretching themselves thin, I think it depends where the release dates fall. Destiny 2 is in September, so it's nicely spaced out from the worst of the holiday season. Ideally the other three would then be staggered out with a couple of weeks in between each release, so maybe RDR2 in mid-October, CoD in early November and then BF2 in mid-November. I don't think that'd be that hard to keep up with but we'll have to see what happens.
I could see SIEA having five or six bundles, like they had in 2015. Something along the lines of a bundle for each of the four games above, a first party bundle (Horizon + Lost Legacy?) and a kids bundle (Knack 2 + Lego something?).
SIEE are far more liberal with their bundles than SIEA, so they'll probably have a ton of them but GT Sport will be the big one for them.
Games published by Sony would still count, wouldn't they? While almost all of heir owned studios' upcoming projects have been accounted for - except for Sucker Punch's new production and a possible Japan Studio work in the making-, nothing should have prevented them from making deals, ala Spiderman. I was told that they have quite the second Party network, and owing to their dramatic lead over their direct competitor, they would hardly need to court partners...
If Sony are funding and publishing a game then yes, it's first party regardless of whether they own the developer or not. Spider-Man, Bloodborne, Everybody's Golf, Journey, etc. are all first party.
New games from Sucker Punch and FromSoftware are the two "safe" E3 guesses (though I'd still caution against thinking they're dead certs). PixelOpus and Manchester Studio (North-West Studio) are possibilities too. No way are Japan Studio at a point where they'll announce a new game though.