All 3 are in their 20's?
Gana is great in a team that doesn't like having a lot of possession and I would prefer if we moved on from that style of play, as it will see us in a relegation battle sooner or later. Schneiderlin is worth a punt at number 8 as he has the physical and technical attributes to fulfill the role fully, don't think playing at No.6 ever really suited him myself.
I dont get your last comment, any club who has fullbacks that cross the halfway line will need a midfield anchor for protection, even the most attacking sides in Europe
Gana is absolutely fine if tasked with the role he excels at.
He is superb at harrying and hassling and regaining possession. That should be his role.