I'm not sure what you mean by "API constraints". That bundle works fine on AEM 6.3. Same thing with "JSP used in the component". There's no requirements put on the JSP (or even a requirement to use JSP) imposed by the ACS AEM Commons Twitter integration.
But if this is the path you want to go down, that's ultimately up to you. My guess is that you are missing the service user configuration. You said you created the service user, but didn't say whether or not you created the service user configuration to bind the service to the service user.