I reckon there has to be beacons around ELW's and terraformables, in system with Zarura possibly or at least very close by. I did not look because I personally detest searching for signal sources. May be worth a look though.
I didn't think of terraformed worlds, that's a good thought. Not sure how long it takes for a world to be terraformed though. Any ideas on how that all works?
There should be those beacons and yet none have been found, it's the mile wide inch deep thing. If you're searching for a needle in the haystack there's a pretty good chance Fdev forgot to think it through enough to tossing a needle in it and they'd never tell you.
At one point people were looking for ALW and ELW that have been attacked and started finding LW's with no atmospheres; are these killed worlds? That was quietly fixed over a past update and they now have atmospheres. However unless someone manually fixes that in EDSM and EDDB that first scan data stays forever and even the fixed updates don't propagate unless you manually wipe your own DB and download current snapshot.
Myself haven't run into any LW's marked terraformed Riftward. Notice the Pristine reserve tag is showing up for everywhere new now.
There's lots of examples where stuff hasn't been thought through past the superficial. Take the prison Kahina was being transported to, Koontz Asylum, which in no way had anything of a prison vibe about it, more of a "this will do".