Hey, you've left out "InsaneMystic" as one of the options! 🙂
Barring that, I wholeheartedly support WA's Frillow scenario. (But even though, I very much enjoyed watching the Fresley kiss at the end of "Smile Time".)
Now that I think of it, it's kind of weird - I find Fred & Willow the two cutest & hottest Buffyverse women (with Fred a tad cuter and Will a tad hotter) and crush quite heavily on either; however, in terms of jealousy I react totally different to them. While for Will, the mere thought of seeing her with anyone but Tara or Fred makes me uncomfortable (I remember that WillOz, much as I loved Oz himself and think it was objectively a lovable ship, was torture for me to watch first time around, jealousy-wise), while with Fred, I would enjoy seeing her with anyone on the above list (even though I have preferences; what I'm trying to say is no ship on the list would make me squirm in my seat with jealousy).