Extensive search filtering and results->PDF in the front-end

WP_Query is your answer for the first question, you will need to create a custom search form, and parse that data, in order to create your custom WP_Query. Here is a link with a tutorial to get you in the right direction.

For the PDF part, I beleive it will be easier to tell the users to use Chrome and use the Print to PDF function, and create an stylesheet for printing that will adjust your site so it will hide what you don’t want to show on the exported PDF.