A complete top-to-bottom overhaul of the terminal:- if you wanted to close the airport you would just leave it alone because in it's previous state it serves your purpose better
Bringing Loganair in to save a deteriorating route:- again, you would just allow it to die a death and then release a press statement saying "Oh deary me"
Paying seven figures for new security and radar equipment:- yes ok it can probably be packed up and moved elsewhere, but I would imagine that would be somewhat awkward and the damn sight cheaper option would be to not buy it in the first place because once again, older and depreciating equipment strengthens a business case to close
Releasing a fairly conclusive myth-busting PDF document:- perhaps they might want some of the myths debunking so in the event of closure it would be harder for the public to say "I told you so", but you wouldn't go to THAT much trouble to debunk them, coupled with other efforts to boost reputation such as the world-renowned world host training all of the staff are doing, and the customer feedback forms/Email address that are being given out in the terminal (and before anyone suggests it yes they are being read as I've witnessed the feedback being actioned with my own eyes).
Seems to me the evidence they are trying to keep it open is stronger than the evidence they are trying to close it, but it's harder for people to see - or they're just choosing not to see, either way