What kind of literature are they referencing? Heidi by Johanna Spyri and Alice in Wonderland?
(Everyone knows the Nabokov one.)
I'd Googled it and it seeems you're right. The only sources I could get were a Chiebukuro answer and a Nicopedia article though. The Chiebukuro answer also mentioned a "Baby Complex".
According to those, the age ranges seem like this:
Lolita Complex - Lolicon 12~15 Years old.
Alice Complex - Alicon 7~12 Years old.
Heidi Complex - Heicon 7 years old and younger.
Baby Complex - Babycon Babies to early age children. (Guess it would be the same thing as "Toddlercon"?)
It seems these terms all originated around the same time but only Lolicon caught on.
