Wilder openly admits that he plans short term, mid term, and long term.
Whilst he probably cant talk financial figures for potential long term targets, I've no doubt that he will be having talks with clubs or agents about players who might be available in the summer or even longer term then that. Why wouldn't he?
It's called long term planning. All viable (and successful) businesses do it to some extent. Its a fairly fluid picture and things change, but you can have a plan and agenda in place.
Wilder marking the cards of a player like McDonald now, is perfectly feasible. After all, hasn't our latest recruit Hogan just mentioned in his interview that there has been a long term interest in him from Wilder....and that his agent has had regular contact with United for a good few months....just in case he became available.... football managers don't just get to the 1st of January and then look on football manager to see who might be available, a lot of work has been done beforehand to gauge levels of interest from the player and his representatives, and to register an interest from the club, with the relevant parties.