I was able to contact the person who coded this and he noticed that the navigation was calling the categories to be ordered by ID:
$navigation = get_categories(‘orderby=ID&order=asc&hide_empty=0&hierarchical=0&parent=’.$sitemap->term_id);
I removed the ‘orderby=ID’ and the navigation is working fine now.
I’ll see if I can do the same for the footer. I’ll also check into the validation errors, thanks for your help!