Download this and unzip it, then go into assets\minecraft\textures\entity and replace steve.png and alex.png with your preferred skin(s).
Multiplayer servers don't automatically load. You have to click "Add Server" and add an IP. Bedrock works differently in that some servers are automatically added.
This is most likely caused by some kind of software that blocks trackpad use when typing. If you've installed anything like this, disable it; if not, it might be in the computer's settings. (Even if you aren't using a trackpad, this kind of software also blocks mouse clicks.)
I would assume they went into spectator mode. (Whether it was intentional and they were trying to trick you, I don't know.)
If you're using a paid account, you need to log out of the launcher and log back in. The cause of this seems to generally be changing your username but not relogging in the launcher, in my experience.
The launcher version and the client version are different. You want the latest launcher version, 2.2.2311.
You should probably be logging in with your email, not a username, unless you know for a fact that your account is unmigrated.
What version did you originally spawn the dragon in? If it was before 1.9 that could be a possible reason, since the End was updated quite a bit then.
Mojang can't reset your individual world. You'd have to load a backup.
Okay, I will (ok, I probably will not, because I am lazy.) If I do end up getting one, I'll check, though.
Attached it. (I think that's the right one, I crashed earlier but it was like five minutes before this, but I'm pretty sure the one that I attached is correct.)
Attached two screenshots. The first is how it looks in other tabs; the second is what it looks like in the survival inventory itself.
I've gotten this issue before and it usually fixes itself when I restart my computer.
The video you linked is fanmade. If you want this in the vanilla game, you would have to make a resource pack to replace one of the existing discs.