help with AF

[ivans75]

Hey guys, happy new year. Been awhile since last time I posted here. I need some help with focus please. Particularly when I try to take photos indoor in a restaurant without flash for example during a birthday party.
I always have a problem in taking multiple persons in a frame (lets say 3 persons), there is always one person on the right or left who appears to be a bit soft (not sharp) even if I use f6. I cant use higher f number as the shutter speed will be too slow (increase blur) and ISO was already in 1600-2000.

Taking photo of 1 subject or 1 person is not a problem, i can use zone or point AF.

I also need to know what is best seting in taking photos during birthday indoor such as birthday party with low light and no flash. Should I use AI servo or AI focus? One shot is out of the question i think. And should I use evaluative or spot metering for objects?

I know I should have bought a flash but thats another world to learn.
Thank you in advance

FYI, lens I used was combination of 50 mm, 70-200 and 16-35 (for wider capture) Canon 5DIII

sample picture (ok this was f4.5 so that might be the problem, i have another with f 5.6 with same problem)
3G4A9380 by Ivan Sutrisno, on Flickr

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I think i deleted some of them as I was frustrated lol, but here is another better example with f5, iso 3200 (doh) 1/125 speed (cant do lower as these babies are moving alot) the baby girl in navy blue appears to be softer than the girl in red dress.
3G4A9557 by Ivan Sutrisno, on Flickr

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Edited by ameerat42 to reinstate images below, in the order they originally appeared (but both same size)...
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3G4A9380 by Ivan Sutrisno, on Flickr

3G4A9557 by Ivan Sutrisno, on Flickr