So the story goes like this.
I have redesigned a wordpress site for a client that has some 30+ pages in Xara. The SEO is about done and soon the site will replace the wordpress site.
The old site will be deleted and the new site with Xara will be uploaded in its place.

My concern would be the following:

1) The old site has over a hundred pages, most were named and not used, somehow those 100 odd pages still linger in google and are indexed and the previous designer did not redirect them with error.

An example can be seen as such, see link below, not sure what the web designer had in mind, ignorance or lack or know how or just did not care to delete them from wordpress.

LINK

My question would be, when I delete wordpress and start with a blank sleight and upload the site done with xara, do I have to worry about those dead links from the previous site?
When will they be removed from Google?

Thank you in advance.