Who do anda think Simba and Nala were planning to marry Kiara off to before Kovu entered the picture?.

I don't know she was probably just going to be a lonely queen :P

I think that was the farthest thing from Simba's mind at the time. I know he might have eventually had to start thinking about it, but at the time I don't think he had anyone in mind.

It's unknown but the filmmakers would have created another lion for Kiara to marry if they feel Kovu is unnecessary for Kiara. a lion cub would have been in the film as one of the pride lionesses offspring.