I wonder if CF was involved or knew about MM disappearance and was somehow taking some delight in the McCann's distress in inviting them over. I hope not.
Just catching up since yesterday.
In my opinion, CF inviting the McCanns around to his place is part of the classic deflection techniques employed by those hiding in plain sight so that if/when his own crimes come to light people will doubt it because "Clement!? No! I can't believe that! He hates anything like that and always been supportive of those who have been hurt by it, look how helpful he was to the McCanns..." or words to that effect.
Someone DH and I know was always very vocal over the years about "paedos" being scum, if the news was on and there was a something about kids being hurt he would always make a remark calling them all sort of names and "how could anyone do that to a child!?", he was active on the PTA, helped run local family events such as Christmas parties put on by the parish council, and so on. Imagine how shocked everyone was when he was met in a carpark by a paedophile hunter group for soliciting sex from four separate decoys whom he believed to be young girls, the youngest of which was posing as a nine year old and the oldest as an eleven year old. He thought he was there to meet the eleven year old. His first defence was to say "I'm not like that, ask anyone around here and they'll tell you I hate paedophiles".