AFK reporting is the only thing they take seriously. You will get a low priority queue and a temp ban faster for that then anything else.
Verbal abuse/negative attitude will get you a pop up warning, but it takes an unrealistic amount of these to do anything. So "no" for this to answer your question
Intentional feeding is a junk report. One team always has to lose, which means that most of the losing team's players will be negative. I imagine Riot gets a ton of these reports for players who just got out played, had a bad game, or lost to a smurf. Too much of a risk of banning players who are just bad or new to the game to act on these reports, even if they have a high frequency.
I have no idea what kind of a loser would report someone for inappropriate name though.
Unskilled player reports somehow (read not at all) affect overall MMR and matchmaking