1. I believe full system scan is 10k per body bonus. Not worth the time or effort to go out of your way to specifically get this, but a token gesture if you do it accidentally.
2. You probably want this. TLDR; map untagged terraformables/ELWs and maybe AW/WWs if you're only in it for the money. I'd say it's probably only worth mapping 1 body per system, or 1 binary pair because the gravity well effect slows you down too much - but that's just me.
Yes full system from my 4 trips since the patch really netted me a small fraction in full system scan.
Terriformable WW's seem to be profitable so I'd go for those as well as ELW's and other terriformables. Then I'd hit the regular WW and Ammonia if they aren't too far away.
Though I always tend to scan ringed WW if not terriformable just for the tag. But yes, that's really about it that's needed. The rest is a big waste profit vs time wise...