1: No I mean the position should change, lets say that the advert is on page 2 on my site, client logs in and edits his advert and saves. The advert should now show top left on page 1.
We update date for every ads after edit, you may change that if in file
$advertisement->date = date("Y-m-d H:i:s");
if( empty($advertisement->date) ) $advertisement->date = date("Y-m-d H:i:s");
Please backup that file first
2: Hard one to explain, I currently re-post my ads on Facebook manually.
True say need debug as your site and how face book parse link.
so work face book, may be will need rebuild your site layout