If Ventus were anyone from the past my bets more on Master Gula or some sort of reincarnation perhaps. As for the whole Dandelion thing I've always speculated that the dandelions are what spawned the whole Keyblade warriors and their ceremonies like what we see in BBS. It's all open to interpretation at this point in time. It's possible Ventus is or was a Dandelion at some point in time it just seems rather unlikely to me. You present interesting perspectives with your points but it doesn't really all add up imho. Interesting ideas and speculation though.
I disagree, not only is there too much solid evidence that can be easily interpreted with Ventus being a Dandelion, but also, Nomura has confirmed that Ventus will be involved in series 2 of Unchained X. The reincarnation theory was originated by Geldaporn during a time when we seldom knew about the Forteller's personalities. Sure, things, elements and events are coincidentally linking the Fortellers with the current Keyblade heroes, but at this moment in time, they're nothing more than coincidences.