Back when Capcom revealed an updated version of Onimusha: Warlords coming to consoles in 2019, one of the announced features was a newly-recorded soundtrack, which includes totally new voice acting. The latest issue of Weekly Famitsu has a spread on the game, and announces a large chunk of the Japanese voice cast as well.
Here is the list, courtesy of Gematsu:

Samanosuke Akechi (voiced by Takeshi Kaneshiro)
Nobunaga Oda (voiced by Fumihiko Tachiki)
Kaede (voiced by Mikako Komatsu)
Yuki (voiced by Kaori Nazuka)
Yumemaru (voiced by Hisako Kanemoto)
Hideyoshi Toyotomi (voiced by Wataru Takagi)
Guildenstern (voiced by Houchuu Ootsuka)
Hecuba (voiced by Mayumi Sako)
Narration (voiced by Mugihito)

Announced back in August, this new version of Onimusha: Warlords, which seemingly retains its original title without any changes, is a new, HD upgrade. It also has a new control sceme, widescreen support, a new easy mode, and of course the aforementioned soundtrack and voice changes. Check out the official key feature list, from Capcom:

High-Definition Graphics ? Characters, background graphics, and cut scenes have been given a high-definition update to enhance the visibility on players? quest to save the princess.
Widescreen Support, New Display Options ? Both the original game?s display (4:3) and more standard widescreen display (16:9) are supported. Display settings can be changed between 4:3 and 16:9 at any time in-game. Specific screens, including parts of the menu scree...