You can - and IMO should -number your own preferences you know, I always do - IIRC this time around the Greens have an official line of voters should DIY.Also, the way they negotiate preferences is by trying for Senate seats, so in this case it's the same difference as far as veto power in the Senate goes.
Doing some quick research I dug up the Greens policy pages on Science and Technologyand Media and Communications - while they have an emphasis on 'net neutrality there's nothing specific about interent privacy unless it's in their full policy document, which I can't really be bothered reading through. I'd say it's still a pretty safe bet they'd be opposed to the filter and mandatory data retention given their broader stance, but it is probably worth emailing them with your concerns about the filter/data retention and asking them what their official position on them is.
I have a friend in the party and will send him a message checking into this - if I can get an official stance I'll post it here.