I think it is ok to mix finishes. I am doing chrome plumbing fixtures and cabinet hardware and ORB light fixtures and interior door hardware. I think the point is to be consistent - it would look funny IMO to have mismatched interior door hardware throughout a house, for example.

I prefer not to mix chrome with ORB in the vanity area. I think of the vanity, mirror and lights as one unit, so I like it to be consistent. I would rather use nickel with its gold undertones with ORB than chrome with its blue undertones.

A quick search on Houzz will show lots of pictures with mixed finishes. The first two below have ORB light fixtures and chrome/brushed nickel plumbing fixtures and cabinet hardware. The last picture has chrome plumbing fixtures and ORB light fixtures and cabinet hardware. IMO all these combinations look good. I am typically a "matchy/matchy" person but wanted chrome plumbing fixtures in my house and prefer ORB light fixtures to chrome light fixtures for some reason. So I have spent hours looking at pictures with mixed finishes and reading design blogs/home building forums and have come to the conclusion that there are no "rules" on this and it is really a matter of personal taste.

I also have the Grohe Arden faucet in chrome. I love it. Something about it reminds me of a Buick from back in the day. I chose a Hinkley Avon light, also in chrome. I really stressed about matching/not matching and am glad I went with chrome for the light, although I don't think it would have mattered too much if I went with a nickel finish instead.

I wonder though if the two styles you've chosen will work together. Perhaps if the light finish was chrome/nickel that would tie them together more. I don't think I'd pair that light with the faucet.