But they need to make further uses of Amiibo in order for it to stay alive.

I know but considering how long Activision milked Tony Hawk and CoD Skylanders is pretty short in comparison. Skylanders was like Guitar Hero..it had a gimmick that was not going to last as long. Tony Hawk and Guitar Hero came back eventually but only after a several year break.

When Cloud and Bayonetta come out the demand will be insane.

It's probably a fad like the Guitar Hero and Rock Band thing before it.

I suppose Lego dimensions can keep on going, since they seem to have a much wider range of properties to work with, and legos can allow for some cool building in their games, although I have no idea how that game works. Perhaps it will go down the same way as the others. Weee shaall seeee.

As for Nintendo, amiibo will probably continue until they run out of characters to use, or people just lose interest in them.

Lego Dimensions you don't even have to build the stuff. Just put the disc on and it'll work.

Oh, then what do you do in the game?

I believe the only ones with an extensive amount of characters to make a NFC line of figurines for, are Nickelodeon and Cartoon network. Maybe have someone work on licensed games, but it didn't quite work out for Disney and they have a bigger catalog.

Probably just be Lego and Nintendo for awhile now until Activision tries it again after a few years break. Might pull another Tony Hawk.

Annual releases of Skylanders are killing it. Every year a new line-up is too much even to collectors. Activison should make pace its launches with more room.
Amiibos are not dependent of the games, so I think they will continue to stick around for a while.