Kiara & Kovu

Mufasa tells simba not to go to the shadowlands because he knows scar's kids(kovu and nala) hang out there.
-Simba forgets about what his father said because he got distracted by the butterflies flying around,anyway,he meets kovu then nala. They see kiara and ask if she wants to play too. They all become friends.
Scar executes the stampede plan, but Mufasa doesn't die.
Mufasa exiles scar and his kids.
A few years pass, and Simba is betrothed to Kiara.
-Scar and Kovu enjoy watching some of Scar's followers burning the pridelands. Nala thinks this is wrong and voices her opinion. Scar and Nala fight,...

I really wonder how do people see "so many plot holes"? Because I can see ONLY TWO and even they are relative.

A plot hole is something that causes the plot or a part of the plot to not add up or to not make sense. These two movies don't have such, as all you have to do is pay attention to what is said and how it is said, and at some points to use common sense.

1.) The cub's design and the ceremony.

But officially that is not a plot hole. As Disney has made it official it is "Fluffy"/Kiara in the movie universe. As in introduced no one else in the movies - basically we just have to accept that...