HELP tackling huge WCAG 2.0 compliance project! Need advice, please

I need advice on how to tackle a really big project.

The project consists of getting the production and future support website WCAG 2.0 complaint - for both mobile and web:

  • Production website: is not WCAG 2.0 compliant and needs to be updated ASAP. I have no assets, just production and a bunch of screenshots/URLs of the elements that in violation.

  • Future state of production website: also not WCAG 2.0 compliant and is scheduled to be updated in July. I have wireframes and a design system file generated by Zeplin.

The new site that's to be released later this year is a total facelift. The color palette I use must be similar to the new design. My goal is to create a new one-size-fits-all WCAG 2.0 design system that embraces the color palette of the redesign.

To complicate matters, the production site has a lot of custom HTML and one-off elements. I'd estimate that it uses 2 to 3 times more colors than the redesign. My goal is to consolidate it as much as I can.

How would you tackle such a big project?

Are there any special tools or plug-ins I should be using that could help me? I have Adobe Suite and Sketch at my disposal.

Sincere thank you in advance for any suggestions.