Not much to be going on with.
You could have a static landing HTM page made purely from Xara to your Client's specification.
The WordPress (WP) site could then be linked to from there.
I would put the WP site in a sub-folder and as an extra path for your main URL: URL/wp/ or URL/SEO_friendly_name/.

In the WP site you can always have a Home link back to URL so everything seems seamless, as it is.

Regarding SEO, be sure to include a good description and keywords in the Meta Text.
Also ensure there is good prose on the landing page that develops these meta.
For main images, give them meaningful Names with filename=image_name.
Avoid Xara NavBars and HiSlide pop-ups.

I usually include an RSS Feed on the landing page to give the semblance of it being "dynamic".
I sometimes have a random image viewer to give the same effect.

Acorn