Hey bud, to complete the shadow thief, its actually the 320 version you need to complete. There shouldn't be a waymarker on the level 20 version but there is, because bungie :( So do that once you've completed the Rise of iron campaign and are 320 light. The patrol one, I assume you mean the quest. First off, it's worthless anyway, meant to give you a tiny xp reward when your very low level, so abandon it. However if you're one of those completionists, open the quest and it'll give diff parts of patrol to do, when do those they fill. I think there's maybe 7 diff ones. Do them all at the cosmodrome, hold out your ghost and you'll see the patrol beacons highlighted, diff symbols for diff ones, so keep doing them until you fill it. The hardest one to find active is the energy wave ones, there's at the mothyards or forgotten shore. If you finish most but not all, it's fine to go to orbit and return, it keeps your progess. You can also leave ones you already have. Enjoy

Are you talking about completing the questlines? In order to do the Shadow Thief Reloaded you have to select the HEROIC version of the strike, not the regular version. And to unlock Cosmodrome Patrols, you have to work your way through the story.