Convert javascript running xml files to wordpress platform

Depending on your skill level with html, css, javascript and php you could build your own theme from scratch or download a free theme or purchase one that gets you close and customize from there. The site you gave as an example states you have WordPress experience so I would assume that you would have the basic requirements for getting a theme to look like you have already.

The site isn’t very large so content migration would be just a matter of copying the content over, loading up any static assets like images or pdfs and building your pages from there. Depending on how much reuse and customization of a template you might use a collection of custom fields and then be explicit in their calls to the template. Or use of a tool like the Visual Composer or other WordPress page builders might suit your needs for precise alignment.

If you don’t have much knowledge of Theme building in WordPress, might I suggest you start here first and come back here when you have tried something and it’s not working as you expected.