I am in total agreement with Nep! There is no reason to port the project in its current form (or any form) to unity, when Renpy and Even RPG maker are more than capable in delivering a quality product. Just look at The Treasure of Nadia! RPG maker is definitely not the best game dev tool, but that game is still a high seller that is loved by many. The time, effort, and funds should be used to pay artists, renpy coders, composers, and possible voice actors to see this project through to a wonderful completion.
If you're reading this and wondering "What the hell are these people talking about?" click on the Patreon link in this page after clicking "more information". Changing engines and the fundamental tools involved in a project are ingredients for development hell.