You can do this with a single auto action per plan or if you've multiple plans activating the same plan they can share the same action. Yes making a new merchandise requires a new action, but that's just a matter of copying the action and changing the plan id. All of which would eliminate the need for you to maintain custom code.

I don't see what such an integration has to do with firing CBs registration triggers though. It does not sound like your integration is coded properly to act on a subscription state change or payment.

Instead of trying to write all of this custom code that you have to maintain I recommend fully describing what you want to accomplish and we find a solution to automated all of this. We do not assist with custom coding so this will become further problematic as you have more issues.

If RSForms is absolutely needed I'd use it entirely for a supplemental purpose. Meaning send them to CB to register and use RSForms strictly for registering for events. This eliminates the need of trying to register users your self.

CB Conditional can be used to condition fields/tabs based off other fields/tabs or static values. So it's very helpful allowing for different profile types. CB Auto Actions for example can act on the before and after registration triggers to handle additional storage needs as well as the before registration form display trigger to modify the form. There's a lot of possibilities to minimize the amount of code you maintain.

Unfortunately as said before I can't suggest much further without a clear definition of usecase. I don't recall the URL to your RSForms page.