I think it dpeneds on the yorkies personality.I was told that yorkies dont get along with kids or other dogs etc..but in my case this isnt true.
I have a 13month old yorkie who weighs 2lbīs,she is very dependant of us and doesnt like other dogs at all,but she LOVES my kids! Infact,my 5 year old daughter is holding her most of the day which she loves.
My youngest yorkie,Jessi (Jessica) is 8 months old,weighs a little over 7lbīs and LOVES other dogs! She also loves kids..she is super social
I honestly think its how they are brought up
My two have been raised with my kids,Lady was alone at first which is why I think she doesnt do well with dogs,as she was 7 weeks old when I got her and was our only yorkie from then right up until she was 7 months old,but she does great with my kids.Then Jess came alone and she went from being with her litter mates,to being with Lady & my kids,which is why I think shes great with other dogs,and great with kids aswell