The yacht photos were marked as having been taken on the 20th, and some photos started popping up the morning of the 21st. It still would've been possible for him to be in Ark on the 19th (if he wasn't filming) and then fly right out. However, I saw dozens of reports about the release of the WM3, and only about 3 of them mentioned Johnny being present, and those were just in passing- no photos, no quotes; most other reports just mentioned his past support. The WM3 themselves didn't mention him being there and neither did their website. More importantly, this was a major news event and no photos spotted him-- believe me, the Depp community is rabid enough that they would be looking very carefully for photo evidence!
As for the Disney thing, I remember seeing something on some site, and when I clicked the link, the page did not exist. Impersonators do show up at Disney or other places sometimes, and some are quite good. It is very doubtful that Johnny would be walking around Disney during regular hours- he has even spoken of this problem himself. Parts of the park (Land, not World) closed when he showed up to ride on the POTC ride after they installed the Captain Jack animatronic. Vanessa and the kids are sometimes spotted at 'Land, and photos do pop up of them but they are surrounded by an entourage. Johnny generally needs more security than that when in public. Of course, any report of a potential Depp sighting is of interest to us fans, but we usually can figure out what to disregard, because as you say he can't be in all places at once, and believe me, sightings occur ALL the time and most aren't real
Best guess- Johnny filmed during the week and enjoyed the weekend with his family.
I do hope we'll hear him say something about the release.