Yes they are the same body...I get the acronym mixed up all the time.
For your second question the region that the tournaent is in is IREVA. If you are registered in another region (say NERVA, WEVA, KRVA or GEVA etc.) I believe that you are all set. We will just need to have your players registration numbers with your entry form. I will confirm this for each case though so just drop me an email if you're interested in putting in a team.
Ben
beaker_1427@yahoo.com