As above, both Kerr and Mayo have been targets of Aberdeen long before Robinson arrived.
I'm pretty sure over the next three and a half months Lutz will target players he knows and who have a more impressive CV, much like he did in January. Of course your ex-Hoffenheim, AC Milan, Bologna, Man City and Bayern Munich players we all signed didn't exactly lift the place. Some players who have proved themselves at Premiership level ain't a bad thing.
Hearts' - with their famous Jamestown analytics and boasts they'll be challenging for the title again - have signed one player so far; a winger from St Johnstone.