It might help to have an Acrobatic Oz Kit on hand for this, which allows you more movement in the air. Head to the very top of the comms facility, after defeating the RedBelly boss. On the east side of this area, jump to the dome structure. Now, for this to count, you will need to land on the actual ground and not the section in the lava river. Run from one side and use as much of the platform as possible before jumping, waiting to air boost until your forward momentum has stopped. If done right, you should land on the ground and get the challenge.
During the boss fight with RedBelly, once you get their health down enough, they will split into their two counterparts, Red and Belly. All you have to do is kill Belly before you kill Red to get this challenge, which is likely to happen since Belly will charge towards you. It seems this is only possible during A New Direction , even though RedBelly will respawn when visiting Crisis Scar again.
You need to travel up the lava river, starting from the fall, without dying. Start by jumping onto the island with the loot chest and vault symbol, then make your way up the shoreline until you can jump to the other island marked on your map. If the challenge doesn't trigger here, then jump onto the rocks below one of the pillars.