Ok, for Thea  i'd say she would be able to control the liquid Nitroglycerin well enough to create Nitroglycerin explosives, but her reign over the gasses is  to  just turn it into liquid Nitroglycerin :P So i guess i did a terrible job saying what i really had in mind when i typed that out. I'd say she could control it up to 12-13 meters away from her. 

As for Lance, he can teleport where he can see or where he has been in the past (and looking at pictures or TV doesn't count as seeing). As for item duplicates, i'd say if it has a bigger surface area then that of the average car he can't duplicate it. Would this be ok?

EDIT- I was looking over this before and i got pissed at some spellin mistakes so here ya go. I was a giant tard and kept saying nitrogen instead of Nitroglycerin cause im fuckin retarded