Possible *Spoiler Alert!* It looks like we know who Richard E. Grant will be playing in LOGAN, and it makes sense.
According to Slashfilm, Richard E. Grant will play a very important part in the film, even though he’s likely not the main villain to Hugh Jackman’s Logan. However, he does have something to do with the young girl we’ve seen in the Logan trailer.

Grant will be playing Dr. Zander Rice, the person responsible for creating X-23, and who may have a reason for wanting Logan dead.
In the comics, Rice is the son of a scientist who was a part of the original Weapon X project that created Wolverine. Zander Rice is motivated to take vengeance on Wolverine after his father was murdered by the mutant in his escape from the lab.
The R-rated Logan will be released March 3rd, 2017.
(Source)