Hi @S-ed,
I think, from the description in the first post, you could guess that it is a “Project based” Tool.
Republic-RT is nothing more than a UE project with some functionalities created using Blueprints (“Editor Tool” then? ). I have bought some VR locomotion systems, (for example) in the Marketplace, that are distributed in the exact same way I would like to do with the tool in the future. UE5 project files that are downloaded from Marketplace.
*Here is a little update that shows how a user could “Transfer” values of the light rig from Runtime to Editor using Sequencer. I hope this shows the nature of the tool in a clear way:
Credits:
“Sia” - The Elf Barbarian by Ernest Nemirovskiy
Music: Heimweh by Fjodor - Artlist
Sure, I have to do a lot of digging before putting the tool in the Marketplace, but I understand, this should not be such a big problem right??? 
You mean that if the project is not stand alone, I could not Register the name of “Republic RT” and things like that?
Could you please be a bit more precise with those legal “difficulties” I could face? Even if it is in a very brief way, I would really appreciate if you could share a bit more of your experience/knowledge in this matter 
Thank you for your interest!