My daughter and I are looking to enter. I assume RTP assets and included plugins can be used, but are we able to use commercial plug-ins? (VisuStella for example) Also, can we use commercial art assets such as Tilesets, Characters, Effecseer, etc from Itch, Steam, and Komodo?

As long as you own it (or have a license to use it) it is fair game! Good luck to you and your daughter!

That is good to here. We will work hard on it!

PS: My daughter says thank you. :)