I've still got them competing in the Australian cup competitions as well, (Australia Cup and Fictional League Cup), but fixture congestion would defenitely start to become a problem.
I like the idea of a Hawaii team in the OFC CL, not sure if I'd use it because I don't wanna touch the CONCAF stuff too much, I found this amazing Canadian db which I don't want to lose.
In my most recent season I noticed Wellington Phoenix ended up getting grouped in the OFC CL after winning the NZ Cup the season before (yes that is a second tier they are playing in)