Hey,
1. portfolio navigation. This is only possible with the premium theme, not with the free sorry.
2. two portfolio carousel, this is also only possible with the premium version not with the free sorry.
As for a list of css variations, there really isn't any practical way to set this up. The list would be too long to the point that it wouldn't be helpful. What you can do and is very easy to get the hang of is right click on an element while using chrome or firefox and in the popup window click "inspect" a tool section will appear and on the right you can see what css is applying to the different elements. That can help you find what selector you need to use.
Kadence Themes