I believe the individual stacks shouldn’t be impacted by the gatekeeper issue. It’s only plugins. So if you are up to date with stacks 4 or stacks 3 “plugins” those should work.
It sounds as if you need to be running the beta version of RapidWeaver(8.4) and some of the other plugins listed above to be compatible with Catalina. If you haven’t upgraded to Catalina yet and you don’t want to be a beta tester, then you’ll be better off waiting.