You have no FF lenses, which mean's you might as well just sell everything and start new with FF.
1. Tamron 24-70 2.8 VC.
2. Canon 100mm F/2
3. 5D2 or 5D3.
Skip 6D, Not good value for $$$.
I WOULDN'T do that - I would skip 5D II and take 6D for these reasons.
1. Newer camera - with extra features, wifi etc
2. True Auto ISO in "M" mode, 5D II has fixed auto ISO at 400
3. Better AF - more accurate then 5D II
In actual use, the 6D will fail in everything the 5D2 will performance wise and no better than the 5D2 in getting the shot. Same FPS, nearly identical terrible AF, and 98% viewfinder. The 5D3 will have none of these limits.
So why waste those extra 500$? Get another lens. Don't waste it on the fluff from the 6D and that's why I consider it bad value for $$$.
In which way? 6D AF center point is way MUCH BETTER 5D II, so what is your point?
your still stuck only using the center point. That's the issue.