Conditional logic on multi-step next buttons and issue icons

Hi Guys,
i got a comprehensive multi-step form with 3 pages and many nice conditional logic fields. All is fine and very good functional.
Only 2 problems exist, i don’t get solved:

1. Show / hide „next“ button by conditional logic.
1.1 How can i hide the „next“ button by default and only get shown after clicking on „yes“ = „sim“ in portuguese language, on a selected radio field?
It should be set for buttons on a radio field at first page and also on another for the "next" button on second page.
There is no option on „show/hide“ settings in conditional logic settings.
So how can we make this function possible?
1.2 Another way on this project would be, to hide "next" button by default. This is no problem by css. But how is the way to skip automatically to next page by clicking „yes“ on radio field e.g. on page 1?
I found „properties“ settings in navigation options, but switching „Automatic Page Navigation“ to „yes“ and adding conditional logic function and also action on radio-field made no change. It does not work here.

2. There are problems with displaying icons in frontend on form component. Font-awespome ist not displayed at all. Material icons are only shown in backend, but not in frontend.
It’s only in forms. In gridbox-editor all icons types are displayed correctly.
I also checked redirection on .htaccess.

Thanks for help!

Regards Thomas