The vast majority of toilets use either a round or an elongated toilet seat. The bolt patterns are standard, so it should bolt in. One thing that can make for problems is if the part that attaches to the toilet is solid across between the bolts. Some toilets are not exactly flat between the mounting bolts, and that means the hinge part that attaches will end up being bowed. That can either make it stiff or not be able to be tightened down at all, depending on the hinge design. All of the Toto seats I've seen do not have the two hinges connected flat between them, they're sort of like towers and independent...ensures they fit better.
With Toto, one of their seats will be a nearly perfect fit to the curve with little to no overhang. That may not be true of an aftermarket one, but it will still work. Same idea with the colors...you can get them close, but they may not be a perfect match. Note, being made out of different materials, depending on the light, they still could look slightly different even with a Toto seat. How shiney, smooth, etc. they are will affect the perceived color. FWIW, Toto makes two whites so getting the closest match can take a little research.