I'm not a fan of Chambers and actually he is our 6th or 7th option on defense behid Mustafi, Koscielny, Monreal, Holding, Gabriel and Mertesacker. At the moment he is away for the Euro U21 and when he will return, I don't know if he will have a place as starter for the friendly game to prove his quality into the back three. The best solution for me is to sell him.
Elneny is the 4th choice behind Xhaka, Ramsey and Coquelin. Arsenal need an upgrade on technical level (a long term replacement for Santi Cazorla) and can't sacrifice the only one BRM in the squad to sign an all-round playmaker. Would Elneny accept to be the 4th/5th choice in the season before the World Cup? He is still young and deserves to play.