I like the profile of player you suggest. However, in this case, Locko is out with a torn achilles and De Cuyper has achilles problems. I'm very wary of us signing players where there's injury issues, given our recent history.
El Hadji Malick Diouf of Slavia Prague looks a really interesting player for this LWB role. 6 goals and 3 assists this season in an admittedly weak league, and he's only 19 which maybe is the wrong type to bring in with Diego Leon and Harry Amass already at the club. Germany have a few promising young left backs that have played further forward (Rothe, Netz, Brown). Miguel Gutierrez is decent, as is Ruggieri at Atalanta.
Players who will have 1 year on their contract left in the Summer, so hopefully would be cheaper, include Nuno Mendes (injury prone?), Theo Hernandez (attitude?) and Rayan Ait-Nouri (Wolves fans quite mixed on him).