Design a Wordpress Template

I currently have a project with a client to undertake the conversion of a static website with a dated design, into a Wordpress driven website. I have the skills to code the backend in to Wordpress, and create the front-end (providing the designer provides documentation as to grid usage, animations and any other UI effects). Wireframes have already been agreed. These will be supplied once selection has taken place. To summarise, these are simply 5 high level page templates that will be used across the entire deployment, with slight modifications made throughout for different page types through typography and so on. There is also a unanimous agreement between myself and client on certain aspects - these will also be discussed upon selection. The assigned designer will be able to assign fonts, colour sets, UI approach and so on themselves. The website must be mobile responsive, and the big problem we're facing is for it to display all of the existing website content on to the new site (and it is content heavy). Therefore previous experience of designing with heavy content would be advisable, but also open to suggestions about how we can do things around heavy content layouts (client site will be shared once discussions are underway). Budget is relatively small, however there will be retained asset work for a long period of time also which will be on an hourly rate.