Price wise a G4560 is about the same price as a G4600 and G4620 on PCpartpicker in the US. Of those I would buy a G4620 which works at 3.7Ghz. The i3-7100 costs less than $15 extra but bumps speed up to 3.9Ghz and adds Turbo Boost up to 4.5Ghz. Considering it's only about $15. I think it is well worth the small cost increase. These price comparisons all depend on your local costs.
While the i3-8100 is a good price. While higher quality, the motherboards are much more expensive and will continue to be until they start releasing H310, B360 and H370 chipsets. Considering total cost it would make a great alternative to the i5-7500. Since you can get a much higher quality motherboard for the same total cost.