Some of my photos are in the below link, please check and let me know if I should consider going for FF and if FF, should I go for the 5D MIII?
For what you seem to shoot af performance doesn't seem to be critical, you can afford to refocus, take a 2nd shot and then pick the best one - in this case I'd advise the 6d, even as underspeced (or overpriced) as it is in comparison to the competition.
I recently compared 5d3/6d side by side for 2 hours, the 5d3 is clearly the more professional gear not only because of faster fps, higher shutter rating and a bit faster x-sync, but because the handling is faster (like double button layout, mfn button, firmware customization). But if you don't depend on this speed gain or the upcoming f8 af with Canon lenses+tc, the investment in glass will give you better results.
If you want a better performing camera, 5D3 is the best route. It won't limit you later on like the 6D could with its AF performance.
True, but what exactly is "later on"? Like 2014 when the 5d4 arrives with higher mp/dr and the 5d3 can be bought for $2000? Imho an advanced investment in lenses can be a good idea, but I'll get the camera body that fits my requirements as they are right now.