Way I see it, if it's just Jack the Adventurer, then it's clear, it's alright to use, and the same goes for all the others; but if it's Jack who uses the gadgets we're all familiar with, and the speech pattern is the same, and the in-world references are very similar, *then* there's a problem. *But*. It's entirely my opinion on that, and maybe Cat's too, but it's very much not a general public thing. The general public won't know these fannish people, and wouldn't recognise a fanon speech pattern if it spat them in the face and used only catch phrases.

So, to answer the first dilemma from my own pov... If *you* can recognise your new Jack as "looks exactly like, sounds exactly like", then you should probably admit to fanfic, but if it's just an adventurer, happy-go-lucky, sexually-open guy who happens to be a captain and happens to be called Jack, then the way I see it, there's enough of them to allow it to be considered original.

I hope I managed to convey ideas with these words. It's a little complex maybe.