Yah Coentrao is ur choice for LB unless U sell sum players and gather sum more money as I got Gareth Bale for 55 Million euros in January and he was awesum. There is ofc Evra and Cole too, but too expensive if U wont gather sum more money.
for CB, get Holger Badstuber. He's great & young, trust me, U wont look back. If U had more money, U could get Thiago Silva