Silva likes to play a front 3. Tosun, richarlison, niasse, Walcott, Sandro, Bernard, lookman, dcl. A lot of completion for 3 places in the team with a lot of those player able to play in more than one position across the front 3. So in that case I'm not confusing anybodies position.
Bernard is a left winger and that is a position I've seen dcl play in for Everton, we also have richarlison and lookman who play in that position. Tosun, dcl, Sandro Walcott and niasse can play down the middle. Walcott and Sandro down the right. So back to my original point a loan move in January when Bernard is up to speed.
First two league games Silva has played Tosun as an out and out striker, not a front three as you describe here. Against Southampton I'd argue Gylfi was more advanced than the wingers for the most part. DCL was used from the wings a lot last season to help him develop his game, as happens with a lot of young strikers. It helps he has the pace and willingness to chase in the channels. He's a striker though, that's his position. Bernard is not. So back to your original point, it makes little sense.