I'm sure the mods will make this point too, but while all of the flairs are happy to answer questions for free on the internet, there's a general distaste for working on books/films/video games for free, especially if they're going to be sold for profit. While some folks here and certainly elsewhere might be willing to help out for reasonable rates, I don't think anyone will want to do freeform historical consultation for free.

Hi there - we're happy to approve your question related to your RPG, and we are happy for people to answer. However, we should warn you that many flairs have become reluctant to answer questions for aspiring RPG writers, based on past experience: some aspiring RPG writers have a tendency to try to pump historians for trivia while ignoring the bigger points they were making, while others have a tendency to argue with historians when the historical reality does not line up with what's needed for a particular scene or characterization. Please respect the answers of people who have generously given you their time, even if it's not always what you want to hear.

Additionally, as amazing as our flair panel is, we should also point out that /r/AskHistorians is not a professional historical consultation service. If you're asking a question here because you need vital research for a future commercial product such as a historical RPG, you may be better off engaging a historical consultant at a fair hourly rate to answer these questions for you. We don't know what the going rate for consultancy work would be in your locality, but it may be worth looking into that if you have in-depth or highly plot-reliant questions for this project. Some /r/AskHistorians flairs could be receptive to working as a consultant in this way. However, if you wish for a flair here to do this work for you, you will need to organize this with them yourselves.