Hello Marisa,
1. No, the Who viewed plugin does not work with the credits. All what can be done is to restrict the view for the widget. If you go to Admin Area > Pages > User Dashboard >> click the Edit (wheel icon) >> check the 'Restrict View' box and select the role this box will be visible for.
If you want the Who viewed Me plugin to work with the User Credits plugin, you need to contact this plugin developer and ask them to adjust their plugin to our credits system.
2. Yes, forum is connected to the User Credits system.
Here are two actions:
Post in forum
Post in group forum
3. Yes, both profile/newsfeed status and video comments work with the User Credits system.
Marisa, you can check out how the User Credits and other plugins work at our demo site: https://demo.oxwall.com/
Admin login details:
Username: admin
Password: demo
Let me know if you have further questions.