Yes, leaving chests behind, they will still be there when you come back.
However, there's a quicker way back if you have some skeleton keys. After the moving pits, you picked up the Ra key from an alcove right? Well, from here, turn left and follow the corridor around until you see the skull on the wall. Pop a skeleton key in there which will open a secret wall to the central staircase. You can then go back up to the Firestaff level quite quickly, assuming you've also opened the skeleton key wall on the level below the firestaff, 'cos that's where the stairs end up.
By the way, your avatar doesn't show up because the site you got it from doesn't allow hotlinking. You need to save a copy of the picture to your own webspace and link to it there. If you don't have webspace let me know and I can put it on mine.
It's no problem about the avatar; I've fixed it for you, as you can see!
If you're on Lord Chaos lair, when you say air elementals, do you mean the Black Flames? The creatures that don't move and sit on a firey pit? There's an option on the Firestaff, Fuse, which will get rid of them very quickly...
Fuse kills Fire Elementals? Cool! I didn't know that! Not that it matters...I just leg it around them or don't go near lol...oh well, you learn something new every day lol