I don't think WebAssembly is going to bring back Flash or Java Applets in any meaningful way. Maybe someone will hack something together and use it for niche old Flash game sites, but it's hard to see a reason for widespread adoption of anything new. People have moved on.
Flash and Java Applets may not be "dead" forever, but they also are not likely to ever be more than undead zombies.
I think we are talking about different things. Half your links have nothing to do with Flash or Java Applets (.net, XAML?).
You seem to be talking about new platforms that may derive some part from the old. I'm not saying WebAssembly won't be used for new platforms as that's sort of the whole point of it.
What I'm saying is that WebAssembly won't bring back people making Flash .swfs or writing classes derived from java.applet.Applet in any mainstream way. In that sense Flash and Java Applets are dead. Maybe someone will hack something together that allows you to run them, but that won't bring the developers back to the old platforms.
If Oracle or Adobe announce something, maybe the industry will jump on board, but currently I don't see anything in your list that makes me change my mind about Flash and Java Applets being dead and not coming back.
As I said, we are talking about different things. I am talking about running binary executables from old platforms and people making new binaries in the old way again, you seem to be talking about porting old source code to new platforms.
The new platforms may use the old languages, but the runtime libraries are not the same. The new platforms have different APIs and functionalities (no threads in TeaVM for instance).
To simplify my point. ActionScript is just a language. Adobe Flash was much more than that. Maybe companies really will find some compelling reason to start using ActionScript again... but Adobe Flash and it's SWFs will still be dead.
Flash and Java Applets may not be "dead" forever, but they also are not likely to ever be more than undead zombies.