Who besides immediate family and attendants count as wedding party?

Vanessa Evans

I've been trying to figure out who constitues as wedding party other than just parents, siblings, and attendants.  Do the famililes other than children count as Wedding party? For example, my cousin is also my MOH.  I have of course invited her children and husband.  Her brother, his wife, my aunt/uncle, and grandmother are all also attending.  Do they all count as wedding party or only my grandmother, and my cousin's husband and children?  I'm sure this is a silly question but I would rather ask a silly question than be incorrect and underestimate our wedding party.  Thanks!

aerinpegadrak

Ditto Stage.  The wedding party just consists of your attendants, including children (like flower girls and ring bearers).  Spouses of the WP and immediate family are usually invited to the rehearsal and dinner, but are not considered part of the wedding party.

bratto06

Only the people that walk and stand up with you are the wedding party...Hope it all works out! 

arimelo

What about ushers, are they considered part of the WP? Do they necessarily need to wear the same tux as the groomsmen/bestman?
We're having 2 ushers because 2 BM couldnt make it halfway in the planning...