I have also recently hear references to Fire 7, but have not found that frequency yet. I'll listen this weekend, and see if I can't find it.
As for OSCCR and REDNET, those can't generally be used for "normal" operations. I have not heard any operations on those frequencies in this area. I doubt they are being used for Island County Fire 7 and Fire 8. OSCCR seems to have some pretty heavy restrictions, especially up here near the Canadia border.
I found a document that outlines the "authorized" use of OSCCR. Interestingly enough, the use of OSCCR is controlled by the WA Dept of Transportation and the Washington State Military Department:
http://emd.wa.gov/1-dir/com/osccr/osccr-idx.htm
Brad/N7JGX
Whidbey Island, WA