That sounds like it might have something, but also remember:
Ah, good point. I wonder what that would do to an interpretation of the dream, though. The sun is presumably the sun, but also Azura's Star. The moon I'm not familiar with, if it has any symbolism outside her spheres. So... hrm. For that matter, the sun is a magicka portal, whereas the moon is... a corpse, actually. Now that's interesting, though the crescent part makes me wonder how literal it is.
So I guess that'd turn the dream meaning into... abandon your mortal shell for magickal power, or something?
If Sharn refuses to teach you for whatever reason, ask her about necromancy. Make sure you’re in the crowded arena so she can’t make a scene. Ask her about her own personal copy of ‘Legion of the Dead’ in her chest at the mages guild. She’ll cave and possibly teach you some spells for free. Try to reason with her first though, we need her later. She might not care about divayths mark but can't hurt for her to think we have friends in high places.
I see very little reason to antagonize a necromancer in a public place in an effort to coerce her into teaching us Restoration. I say we focus on making friends and allies over alienating everyone in an effort to squeeze every last immediate advantage out of them.
Anyway, as far as instructions from Mages Guild -> Arena go, assuming we need them:
Assuming everything's vanilla, which we know it isn't, you should start on a stone platform overlooking the Vivec Mages Guild. Go straight down the stairs, past where Trebonius is sitting in Vanilla, all the way up either staircase to your sides, and out the front door. It's not hard to get out of there.
Once out into the courtyard, go ahead and take the large door to your right outside. Down the stairs and curve hard to your left to take the waistworks door right next to the stairs. Once inside, keep curling to your left down some stairs to the lower waistworks.
Once you're through a door near a balcony, take your first right. There should be a door directly in front of you and two long hallways to either side. You want to keep going straight, through the nice close door, which leads outside. You should be facing the canton you're trying to get to next, but there won't be a bridge in front of you. Take either of the ramps to your sides down, then curl back towards the way you were facing when you came outside.
That should lead you to the main bridge leading from Foreign Quarter to Redoran. Scurry across, turn left, and follow the path around to the next bridge. That's the Arena, and you'll want to get to the highest point.
To get there, just take whatever ramp is closest, then circle around the upper outside level until you get to one of the big staircases leading in.
So yes, this should get us quickly and easily from the mages guild to the Arena, assuming that's what we're doing and nothing's radically reorganized.