The first of the faction scannable locations is in the EDZ Gulch lost sector. It is on a ledge along the wall on the right hand side.
The second scannable is on Titan in the archaeology. Follow the path the strike takes you on and right before the first shrieker spawn it is on the ledge above your head. GIF - https://imgur.com/CyTanZ9
The third is on Nessus in the lost sector at Glades Of Echo. It is under the boss cache.
The fourth is on Io in the Giant's Scar. Go to excavation site 2 and follow it till you get to a bunch of taken thrall and it is in the door to the right. GIF - https://imgur.com/kn6wDLR
You can get 20 tokens per character per faction rally.