Hi,
I can start now, I have gone through your project ("Prestashop 1.7 disable defaulft combination
") requirements and found myself as a best available freelancer for this project. I can fix all 3 task quickly.
I have Completed many complex website in PHP and Prestashop with custom Module/plugin and templates including Booking, wishlist, Security, shipping, Multi Store, Auctioning, Multilingual etc.
I have more than 8 year experience in PHP, Wordpress, Prestashop, Javascript