The boxes, as soon as you make a choice, go to another page, yes? They are searching a custom post type named ‘inspirations’, yes? And the selections are custom taxonomies?
It would need to be one form (you can place the ‘or’ by using custom CSS to use the before pseudo class to add content).
The fields must each have their own custom taxonomy. This means you need three separate custom taxonomies.
The form must be set to the Post Type Archive method and these options need to be set:
On the General settings tab:
Choose which kinds of pages S&F will try to do this on -> Tag, Category & Taxonomy Archives
On the Display results settings tab:
Enable filtering on Taxonomy Archives