YES! I prefer to use them. They're fancy.
No! The writing looks cleaner w/o the extra comma! :)
Yes to Oxford commas! They help with clarity: http://25.media.tumblr.com/tumblr_m5it9oGl1e1qduhpqo1_500.jpg
Oops, not sure why the spacing of that response was all weird. Strange.
Yes to the Oxford comma. It makes it easier for me to read.