In a workflow action, is it possible to assign which action happens first and which happens after that and so on and so forth?

I don’t think it’s possible to do this inside of the action itself. I think the mechanic that’s intended to be used for enforcing a specific order in SuiteFlow is to create multiple states and then create transitions from one to the next. But you should double-check whether you really need to ensure this, since adding more complexity usually makes it harder to maintain and troubleshoot it later.