I would suggest you stay with your initial thought of the 5DIII being your dream camera. The extra you will pay for the 5D over the 6D will seem small a few years down the road. The 6D is a very capable camera for doing most things but I think you would be always wishing you had went ahead with the 5 if that is what you are really wanting. That is what I did myself. I picked up the 6D and took some pictures with it at a dress rehearsal for a high school play. I already had a 7D and was used to the controls and size of it. Not that there was anything wrong with the 6 but I knew after shooting with it that night that I would always regret not spending the extra and really getting what I wanted. So I returned it the next day and got the 5. I love my 5DIII. There are people who love their 6D and rightfully so but if you are really thinking the 5 is your dream camera I think you might be disappointed if you don't go ahead with it. They are coming down in price as at some point the mark IV will eventually be out.
As far as the 24x70II. I really can't imagine that you wouldn't be 100% satisfied with the sharpness of it. Mine is sharp as a tack. You might want to think about a 70-200II. Really useful lens and is also very prized for portraits. It is by far my most used lens but I take a lot of sports pictures.
Not knocking any of the suggestions from the other members or trying to talk you into spending more than you need to. I just feel that in the long run it is cheaper to buy what you want rather than trying to settle for less than you really want. I am a believer in saving up until you can afford to buy what you want. The dreaming and waiting is part of the fun.