just pretend they died in childbirth or... Simba or Nala
got so hungry they ate the other cubs (that would work with
the oulanders!)

well,it may seem unrealistic,but on films anything can
happen like,somebody turns into a lion for example,in the
real world that can't happen....so i think it's like
that,anyways,if there were more cubs,the story would not be
the same.

actually if there were more than one cub the first born
would get the throne

Yeah, I've noticed that big casts get distracting. Like in
my stories, my main character has at least five siblings,
and probably around that many half-siblings, but only Pete,
one of the half-siblings, is ever really introduced to the
reader.

Remember that Mufasa had a brother, Scar, and this is why
there was conflict between them, and Zira had more than one
cub, right? So not every lion has just one cub, but still, I
agree it does seem unrealistic that most of them have only
one cub!!!

i believe that is because disney directors would find it
very difficult if the lions had more tha one cub because
then thay would have to add a lot of extra things like who
will get the crown, conflicts, etc. so i think is best to
say one cub is better. and if u still find it unrealistic
that topic can be a great fanfic!