How to display fivestar average infos?
Have you gone to Display Manager
/admin/structure/types/manage//display
and played with those settings by the gear? 

I normally setup display types like "default", "teaser", "teaser- icon side", etc. Then when I create a view, instead of outputting "fields", I output one of these pre-setup display types. I use Display Suite to help get more control of them. 

I'm using this votingapi widget in D8 in this way and had no issues.