You would garner far more attention via your Facebook page, and if you have it as a contest, then the topic if payment will never come up. Otherwise, this would be viewed as a commission.
Also, I suggest you brush up on your terminology, as there still seems to be some confusion on your end as to what I meant by concept and production art. Sprites are not concept art. Gameplay video is not production art.
Concept art is the art that fleshes out a concept. The artist
conceptualizes the characters. Concept art is rarely, if ever, final, as changes are made from concept to production to final product.
This is an example of concept art.Production art is art used for reference and the production of the final product. Production art may also change, but it maintains more consistency than concept art. Production art for games may include model sheets or character keys that outline the character's animations. They may also depict a scene, or simply a rendition of various characters for another artist's reference.
This is an example of production art.Model sheets, also called character keys, are pieces of production art that depict a character at various angles, along with provide expressions and details. Model sheets are used for animation, primarily, so the animators will know how to draw a character at all angles and remain consistent with their details.
This is an example of a model sheet.When I asked if you would be able to provide concept and production art for your characters (since I was under the impression that they would all be fanon), the above is what I meant. But since you're using canon RMs and characters, then the art is already widely available.