I guess it's easy to toss out a question like this and see what kind of fish flop into your boat. But your question raises more questions than can possibly be answered.
You say you want a lens for "street photography" AND portraits. Then you throw in "larger compositions." Larger than what?
The term "street photography" is now so nebulous that it means virtually nothing. If you're planning to do "old masters" style street photography (candid people in public places interacting with one another and the physical world) then you'll have no choice. The 35mm is what you'll get. If by "street photography" you mean typical tourist pictures -- buildings, crowds of people, monuments, etc. then the 24-70 is the clear choice.
The classic portrait lens on a 35mm camera has been typically 85mm to 135mm. If you plan to do classic portraiture, then none of those lens choices are appropriate. If you mean something else by "portrait," then you'll have to better define what you mean.
You mention "image quality," but again you don't say what that means to you. Pinpoint focusing? Bokeh characteristics you want? Color renditions? Distortions? Vignetting? Only you know what that means to you.
Finally, there is such a wide price differential in those lenses, I'm puzzled by the cavalier nature of it. The Canon 50 is in the $350 to $400 range. The Sigma is at $900 and then you jump to $2200 for the 24-70. You can get five of the 50mm lenses for the price of one 24-70.
Seems to me you need to answer some questions before you start asking questions.