You can change a site’s layout and style without changing content by editing the CSS files it links to.
It may help to give more info on how the sites were created. With templates, CMS or handwriten.
I suppose it depends on how ingrained the php is; t could be just as easy as coping the php code to the separate divisions. I would setup a localhost on my PC and try coping one part over at a time and see what happens.
I would say trying to do it over Skype etc. would be very difficult.