This is just my impression, I could be wrong, but I feel like I want to give Mackay some credit for this turnaround too.
I remember when Mackay gave this first interview:
When asked what he's looking to do he doesn't say things like 'bring in exceptionally talented players', or 'play elite football', or 'use world class technology', it was all 'everyone pulling in the right direction', he wanted a 'people catcher' as head coach (would soon choose SDG). Then they went to get a backroom team of all Hibs people, which I think we were all excited by, but also raising an eyebrow wondering whether it was sensible.
Then in signings he was talking a lot about 'character' and pointing out that we were signing players for that and not just for ability.
To me, it all seems that that's what's happened since he came in as director of football, and since he put SDG in charge.
I wasn't sure about him when he came in for reasons already well discussed on here, but I have to give him a lot of credit for what it looks like his role has been in building the desire in our squad and appointing the right people.