Borini was bought from an Italian club that he went to after his Swansea loan, Parma or Roma I can't remember which.
As for Joe Allen I seem to remember there being a big fuss about this because they activated some clause in his contract which effectively left Swansea utterly helpless. So unless any of the Southampton players have release clauses then I doubt we'll see any movement from them to you unless it's for ridiculous sums of money.
Allen didn't have any such thing as a buyout, their pretty much unheard of in english footy mate, and even should he have one - Errrrrm wouldn't that have prevented Rodgers bidding on him anyway regardless if they had a signed agreement that he couldnt bid on any player?
Otherwise what would even bw a point of such an agreement, the club can reject any bid on any of its players anyway without any need for such a written agreement preventing the old manager - so wouldnt it be to stop him bidding on players buyouts that woudl actually be the thing that amde sense havign this agreement?
As it happens any such agreement would be worth zero anyway as it'd breech all sorts of players rights on freedom of work and movement etc
Sound s100% like utter bs paper talk, in the same catagory that constantly links transfers with swap deals that never happen outside of FM and fifa