Though there are a number of habits they have the major ones are as follows (also keep in mind my characters are anthro)
Vernon - 'Blushes and turns away' usually means he is enjoying himself but is too afraid to say that because he belives people will think he is weird.
When he actually doesnt say absolutely anything and goes dead silent... That is when he is having a bad time.
Azreth - Generally dislikes 'simering down' while he talks, he will walk around, gesture a whole fucking ton, and if he really likes someone, he will likely get very physical, like poking and grabbing just to entertain his other senses while he talks... He does stop when he feel like the person genuinely dislikes that.
This is also true when he is in his dragon form... So watch out for the massive weight suddenly shiftting your way.
Grey - Grey is actually the opposite, he has too little habits and tics... That is because he supresses most of his tics to maintain his 'tough guy' persona... He does let his guard down when it's just him and hijs mates and he does all the stuff cats normally do, including purring.