OK, so all those things are still mysteries: Amy's boyfriend, the black figure, muppets Odin (this expression is so strange that I can't pass it over as a quip by Joss), the strange tattoo (and who are those guys killed in a church, and are they related to the black figure?).
And how to interpret "I miss that sex".
I choose to interpret it is as a big semaphore signal from the authors to the audience that AR is no longer an issue for them (and for Buffi) when it comes to Spike/Buffy relations. If only they could shake off another cop-out after Seeing Red: Kennedy...