raises hand (you should've seen this one coming)
This will of course result in "I don't like Advice Animals, therefore they cannot be a meme harr harr" reactions. So I'm going to go ahead and just say that all those opinions will be ignored. That's not an argument, that's an excuse, and a very bad one as well.
It certainly has the spread that an entry seems reasonable, but the question is how many others are out there. I have digged through brony advice animals before, and this is most likely the biggest one. The second biggest is probably Rabid Idiot Brony, which has over 200 variations on MemeGenerator (just 10 on Quickmeme) and an own Tumblr blog of over 100 pages (a lot are question answering as well). Whereas Socially Awkward brony mainly focusses on the awkward situations of being in an internet fandom, Rabid Idiot Brony puts more attention to the annoying forceful side of the fandom.
I am unaware of other big ones, but can probably find them if I dig a bit deeper (you are free to help of course). Advice Animals are a part of every fandom (some more than others), so it wouldn't suprise me.
So perhaps a solution, in case there are indeed more out there, would be a header in the main MLP entry. With headers for stuff like conventions and cosplay another for this is doable. Remember though that the main entry is not a reason to avoid seperate entries all the time. If it's big, it gets a seperate entry, regardless of how much people might dislike it.
Pokemon has multiple sub-entries that focus on advice animals (like Pokeparents and Professor Oak). So if it stays to just those two (Socially Awkward and Rabid Idiot), 2 sub-entries for them is a perfectly legit option.
Introductions:
I don't need to introduce myself, as I was the first one on Popper's list.
(got owned)