Hi, I am new to Freelancer.com, but have extensive experience working with PHP, HTML and Wordpress plugins.
I have only created 1 Wordpress plugin before for my own personal use. It requires the installation of other plugins to work properly, but I can send it to you anyway if needed for your reference.
I have also created a child Wordpress theme, again for my own personal use. I can provide it as well if necessary, for your reference.
I am confident I can deliver the quiz plugin you require. The only possible hurdle I foresee is the merging of text with image to produce a PDF. However, having done a cursory Google search, I am confident I can solve this issue, albeit with a little time required for debugging purposes.