Regarding Martial.
Hehehe.
Unfortunately for the huge outlay, we will only keep him if he is outstanding. If he turns out to be average and sits on the bench most of the time, then he will get sold.
When you pay big money (eg, Di Maria) that player needs to start games and deliver. If he turns into an average player, he will be sold on.
Examples are: Di Maria, Veron, Bervatov - the moment you are "average", you are out.
Martial will need to prove himself over the next 2-3 years and "average" won't cut it.