Black anodize w/ teflon seal

A. That will be totally dependent on what a "Teflon seal" is.
Basically there is no such thing, as the teflon particles are larger than the anodize pores and thus cannot penetrate. Seal normally means the colapsing of the extreme top of the pores.
Most "Teflon" is a slurry of fine teflon particles in a matrix of something like a silicate which dries to a consistency of thin concrete.
So, your surface is going to have a blotchy coating of the matrix material, normally white or gray.
Now, if you spray paint it with a true Teflon coating, it will be a very nice cosmetic finish and a LOT more expensive.

A. How are you using the word "seal" in "Teflon seal"? The Teflon molecule (1) is too large to enter the anodizing pore and (2) does not hydrate the aluminum oxide. The Teflon "coating" lays on top of the sealed (hydrated) or unsealed coating and only very slightly skews the "cosmetic" appearance. The commercial Teflon products can be applied on top of black dyed and properly sealed (hydrated) anodizing, but the Teflon is not a "seal", it is a top coating and except for a slight gray tinge, it is transparent. Some years back, in the Baltimore area, someone was developing a method of occluding (not "sealing") Teflon in the anodic coating as it was forming.