@Siddas.
1 thing to bear in mind is that all these players you're thinking of selling (with the exception of the keeper) can be trained next season with extra positions to hold them at 99/119%. The following season when they drop to 79/99% they'll still appear on negotiation lists. The 79% players at level four, where they'll appear as 5 star players. As long as you level up, that is.
Hanging on to them for another season will save you resources by not having to buy new players for next season. They're all good enough to warm the bench.