I agree with @Comfy, I'd be okay with O9 having to cover in defence during a game if all our defensive options were exhausted, just like LJ uses Gooch now and again covering left-back, but for me we need to use O9 strengths in midfield.
Don’t think moving onien into defence to accommodate evans is needed though, pick the right player for the right position let them fight for it that’s why LJ wanted 2 players for each position there’s is no need to start putting square pegs when we have good defensive options