I dont think Neymar will sign for us but assuming he, PSG and Utd wants to sign not sure why his wage(40m) will be a problem, especially if Eth thinks Neymar will be a good signing.
If we want to sign top players of Neymar ability we have to pay close to 350k (I think Kane wages will also come to this number) atleast in wages ,which itself will come to 20m per year. So we are just paying 20m as loan fee which I think is not too bad for players of Neymar ability.
Sure, (on top of how he will fit in Eth's playing style) there will be question on what is the point of this loan, would he joining next season if this loan is good and how much would he cost then and would these wages will be included in the fee etc ..