Yep, that's what that Gaffer's Fix Your Timestep article is. It combines FRL and DT and if I read it correctly it has jitter correction in it too.
No, it isn't, it doesn't, and it doesn't in that order. The timestep is fixed so there is no need to use a delta multiplier. It combines FRL and Tweening. It doesn't have jitter correction, but that's because you don't need jitter correction if you do it properly in the first place. You only need jitter correction if you're A) doing your timing wrong or B) ( reportedly, I haven't witnessed it as I don't use it ) using Max2D, which seems to have problems when background tasks are involved, which don't happen in other engines.