Often the most humble thing we can do is simply say "we dont know" to things.
Since 2013 marked the point at which the SSPX started going wayward, it seems like they were just being impatient and wanted to pronounce quickly on the thing.
It will be sorted one day. When Rome gets back on it's feet.
As for your earlier points about validity. The mental state, messing around, all of that are contributing factors, but what we would be trying to establish, to be precise, from talking to Archbishop Thuc himself, is what exactly his habitual intention was in relation to the Sacraments from the point at which he did the Palmarian consecrations. Because by going directly against the mind of the Church a cleric may have changed his habitual intention in the bad way.
Honestly, it is unlikely, in my PERSONAL opinion that he had changed it. But when it comes to the Sacraments... "ah sure it's good enough" won't cut it. It just won't. But now we can never know. And Our Lord has already judged him, (in the final sense) so we must pray for his soul, and stick with what we do know for sure which is that we have been given a line that is certain in it's validity, and be happy with that.