Hi,
I am the top Joomla developer here on Freelancer.com site (https://www.freelancer.com/freelancers/skills/Joomla/)
I have worked before with quiz components, so I am familiar with it. I can't pretend that I have understood everything, so the best will be to make eventualy a screen share and talk by voice to have a quick presentation about required tasks, but as I far I have seen it is doable.
Anyway I am very confident that I can do this project, as I work only on Joomla development, I have hacked many Joomla component, and created also many, please check my past projects for reviews and to see my expertise.
Regards,
Andrei