Personally, I don` think that`s Mheetu. I think that if it was supposed to be him, his name would have been mentioned in the comic.
Also, if that`s supposed to be Mheetu, why is he depicted as a baby? I thought he was supposed to be older than that. Younger than Nala, but not an infant..?
There`s no reference to the baby cub at all, no gender, no name.. But in other TLK comics there have been appearances by cubs (both Simbas age and younger) and no info has been given about them either. So I think this is just another one of those random comic cubs.
But I don`t really consider Mheetu as a character, because he doesn`t appear anywhere. Why would he suddenly make an appearence in a TLK comic? And why wouldn`t the writer make it clear that this baby cub was Mheetu?