In my (limited) understanding, running your source code using a GPL-licensed interpreter to run the code is not considered _linking_, and thus GPL would not infect the code in question. (This is what allows even prorpietary code to run on top of OpenJDK, which is itself GPL-licensed). In Ruby's YARV interpreter case it's even more straightforward — Ruby License is essentially "either our custom or BSD-2" (https://www.ruby-lang.org/en/about/license.txt), so no "infectious copyleft" happens when running software with YARV.

I'm a little bit uncertain with what you mean with "prevent an end-user from re-publishing", and what's a desired behaviour here: licenses differ in who they consider to be an end-user (that's the main difference between GPL and AGPL, for example) and if they give any end-user a blanket permission to **obtain** the source code (that's the most substantial difference between copyleft and permissive licenses).

WRT business models on top of FOSS — I fully understand the struggle. I cannot possible give any meaningful advise in hokusai's specific case (and arguably I'm even less qualified to do this than commenting on licensing intricacies, please keep this in mind) — but the successful business models in FOSS I've witnessed range from "this is our GPL-licensed code, but you can buy a proprietary non-copyleft rights from us if you're a commercial enterprise" to "this is your GPL-licensed source; if you don't want to deal with its', pretty complicated, compilation — you can buy binaries from us" to "hey, this is my Patreon/Github Sponsorship — if you want new releases to keep coming, put some money where your mouth is".

Feel free to email/message me (link in the profile), maybe I can help you find a setup which would be the best match to your ideas of how it all should work — hopefully without putting the further adoption of hokusai under unnecessary risk... (But, again, I'm just a random guy from the Internet, and all this would be just my pretty unprofessional opinion...)