Thank you for writing in, I did check your site and I don't see any installation issue in there besides the 2 instances of X theme.
Please understand that unlike the Classic Elements, V2 Elements does not adhere to the Theme Options directly. As you notice V2 Elements has a number of configuration on its own (including colors & font-family). If you need a button that directly adheres to the Theme Options settings, please use the CLASSIC BUTTON element instead.
You can configure one V2 Button element the way you want your button to look like and then save that styling as a Present. Present are element level template that can be applied to the same element.
Hope this shed some lights,