There is a huge difference between Lion Guard and T&P show and and I can't really understand how you fail to see that.
The page for the show is here because it's an official Disney show, however it is not, and never was, meant to be part of TLK canon storyline (like it or not, Lion Guard is). Unofficial comics and SNA are still okay, because they were made in the spirit of the movie(s), but if we allowed to make characters for a show with very little logic and no realism boundaries, it will be the only time TLKS is going to turn into a sparkle source again.

SnowLeopard: I'd have thought you could base a character on any universe, just so long as you stated exactly which universe.

I think Sparkle characters are allowed if they are indeed based on a film featuring Sparkle characters. You just have to weigh up to what degree that film/series is ''Sparkle'', and go no further.
So, for example, blue-eyed, brown-furred adult deer are allowed on Bambi Source (seeing as Faline in her adulthood has blue eyes) which is (to my knowledge) unrealistic because only baby, piebald and white deer have blue eyes. If you get my meaning

I agree with your point about having a section for a film we cannot have anything to do with. Even if ''Timon and Pumbaa'' is considered, or actually is, an alternative universe of Lion King, aren't fan allowed to create their own AUs? (Even though I'm not sure why, because it also states in the rules that:

''- Alternate Universe characters are not allowed
Your character can be introduced without taking part of importants events of the movie, but DO NOT change the events that happened in the movies (or any other canon additions). You can't create alternative plot of the movie or create alternative profiles of official characters. ''

But maybe this is besides the subject.)

But it's still part of the TLK franchise. What's the point of having a section for it on this site if we aren't allowed to have anything to do with it? Besides, TLG has magic and sparkle characters. And I'm not sure if it is considered canon with the original movies.

I thought it was already settled
Comaring Roar Of The Elders to anthopomorphized time and space travels of Timon and Pumbaa is far too brave. T&P is meant to be a completely unrealistic comedy while TLG is fairly realisitc wit a little bit of light fantasy elements.
Timon&Pumbaa show is not meant to be a part of TLK canon while TLG is.