Maybe dumb questions here, I'm trying to follow your posts and I may just be confused. First, when you say "Disney Rep," who exactly is this? A travel agent? Someone you got when you call the main WDW reservation line? If Disney (and even many TAs, unless they are WL pros), I would be very skeptical about anything they tell you about views, floors, rooms, etc. You may luck out and have a CM (or TA) that knows what they are talking about, but potentially you don't. Especially with a floorplan as nuanced as WL... I would trust experts here over anything "they" tell you.
Second, I really don't think "WL" when I think of resorts you can see MK/fireworks from. Sure, you can get some decent views from upper floor rooms facing that direction and some level of view down by Geyser Point (I think), but this isn't exactly the best view of the various MK viewing options, in my humble opinion. Sorry if you know this, just want make sure.
If I were in your shoes, I would request an upper floor and likely leave it at that.
Again, sorry if I'm missing something in your posts. Please ask away, lots of people here that can help out.