I think this lines up generally with PUFAs/increased serotonin/increased cortisol being associated with ASD (autism spectrum disorder) symptoms. Very nice that you keep collecting these studies!
Not specifically related to PUFA, but more to the endotoxin part, I have noticed that a lot of people I know with ASD have somewhat of a "pot belly". The evidence here is of course anecdotal, but I was wondering if this could be bloatedness associated precisely with endotoxin? The correlation with increased bacterial activity in the gut seems likely via the serotonin/cortisol connection in people with ASD, and I guess increased bacterial activity could lead to bloating. It would also line up with what you have mentioned for long distance runners in this connection, the "subclinical Cushing's disease", if I'm not mistaken.
Could you kindly comment if you consider this makes sense? Much appreciated!