Thanks for writing in again!
I would like to tell you that all the feature of X is available in PRO. That means you can use pro theme like you use X.
Regarding the fullwidth question, you make the site full width like X. Theme option and choose the page template to no container header and footer.
Regarding the menu questions it like X you can change it through theme option with respect to their stack.
If you have done the header using pro Header builder then the option is more flexible than theme option setting.
You can change the color style everything via header builder.
Just select the menu and the link option and you will find the bunch of setting to make the menu style as per your requirement.
I would encourage you to please check the header and footer builder Knowledgebase article first.