Hmmmm

I don't think you can.

If you could, it would be a very slippery slope. Some artists have styles very similar to each other by chance; should an established artist be able to "sue" a newer one just because they happen to share a style?

Tracing/copying art directly? VERY wrong.

Using a similar style? It's fine. I don't think artists should purposefully copy another artist's unique style, but at the same time it's not something that you should be able to sue over legally.

(If so, Disney would be able to shut down half of FA, heh)

ooo a lynx and a cabbit. oh wait what are we talking about?

I don't think you can copy right a style, from a legal stand point anyways. However, a style can become unique and synonymous with a certain artist, this doesn't mean others can't do it, just means they're known for it.

Yes, you can have a specific art style to a particular artist. For a easy examples, think of Peanuts, Garfield, or Calvin and Hobbes. Each one has a very specific art style unique and instantly recognizable to themselves. The only time you ever see the same "style" is when someone makes art in tribute, homage, or parody of the original.

Unless one is copying that art style to pass off their own art to create fakes, would I think of it as art theft/forgery. Hypothetical scenario, A famous artist (A) dies, another artist (B) makes art in (A)'s style and tries to pass it off as (A)'s artwork to sell it for money/gain.

Tracing, recoloring, or altering the original images is art theft.

I don't think you can actually "steal" an art style. Mimic, trace, heavily influenced by.. yes~ Tracing would probably be the most controversial if that is the case. But using someone as reference should never be considered stealing unless your trying to literally copycat them. Learning to do a similar style should just be used as a tool to improve yourself.