Everyone, you can start each book right from a new game, you just skip the stories of the other books, so to try the new Book 4 Love Route you just need to start a new game and click on the lower right sphere on the map. The choice between Love and Slave is given to you right away.
For the guy stuck on Book 3, try talking with everyone you can in the game looking for something new, not just the ones mentioned. Usually it is kinda impossible to miss content, save for some extras here and there, because the story stops outright until you find it... but sometimes what you need to find is not exactly just what you are told to.
About Temp, I thought it was a brain fart of the protag and he used it because it is a temporary body, but I guess you guys think it will be our Avatar's name there later? Makes sense, since he has no idea of the original name anyway and no one told him so he can't pretend.
And about Shady, are you guys sure you are not with some auto-skip on? New lines would be shown but repeated ones would skip. It seems he has some invisible lines there to cound your clicks around to see if you don't feel like helping him?
I do have a problem myself though, it takes some times clicking on the wind cloud under the wheel for it to be counted, I think it is more reliably right after the border between wheel numbers but not sure?
I... don't get Mercury Bending coming from normal Metal Bending, to be honest. Sure, it is liquid metal, but normal metal bending comes from manipulating the impurities in the metal - the more parts in it that have earth inside, the easier to do so. But as a liquid metal manipulating the solid Earth impurities in it would just remove them, not bend it.
Meaning it must be something new, just like Lightning Bending to Fire Bending - we are outright told it is not something most can do, and even Iroh seemed to only be able to redirect it if I recall right?