I agree that the shots are very nice, and that the lighting, composition and lens choice are great. Not a huge fan of #2, but that is a personal preference. I personally would back off a bit on the skin smoothing, but that is more personal preference as well.
All are with natural light. A few have a reflector. I dont shoot sports, but for portrait work this lens is great. Focus is good in low light and fast enough. It flares a bit in direct sun but not a $1000 enough difference for me. I think Sigma is beginning to put some quality lenses together. This and the 50 1.4 are the only ones i would recommend from them now though.