My own view would be we would try to secure a few for Fatawa, and make a final offer for Dibling, if it's rejected go forward with Fofana.
The thing with using a decoy though, is you actually nees to be credible with your alternative and prepared to go ahead with it.
Aside from that, if they have blinked first with a 2nd offer, that does show a lot of weakness. Everton can legitimately just say our offer still stands.
Thinking of it, they may be trying to call the players bluff a bit as well, and get him to formally put a transfer request in. I.e we offered him to Everton, they didn't do it, you need to play unless you tell us not too. It's the exact sort of stuff we did under previous regimes to young players, before selling them to make them into the villain.
If the last says I want to go, difficult to see where Southampton go.