Remember how Simba tells Timon that he had a bad dream? It's probably not too hard to guess what his dream was about.
Fridge-Heartwarming: Ever notice it seems a coincidence that Timon and Pumbaa don't find their trademark oasis until the morning after they forge their friendship? It dawns on one this isn't just a contrived plot point. The Central Theme of the movie is that "Home is not a place but a people", as Timon later learns after his final encounter with Rafiki. If anything, Timon (being as Literal-Minded as his mother claimed) was looking at it all wrong when he was trying to find his new home based on the farthest point. But then Timon looked beyond (the stinky warthog) he saw and found a friend.
And in the ending, Timon also brings his mother and all the other meerkats to the oasis, in a way, he's bringing Rafiki's advice full-circle. For all their existence, they only believed that living should be done for the sake of digging and surviving any hyena attacks. Bringing his family helped them comprehend how meaningful life could be once they looked "beyond what they saw".
When Timon tries to make a Call-Back to Mufasa's Circle of Life speech about how lions "become the grass" that their prey eat, he's a bit closer to the mark than he realizes. Meerkats themselves don't eat the grass, but many of the bugs they eat do, thereby providing the connection that completes the Circle of Life.
This makes even more sense in terms of the film's plot. Some of the events of the film contradict those of the source material, but Rosencrantz and Guildenstern are forced to follow the play's events to a T. The same could be said for Timon and Pumbaa: they're literally going through the exact script of The Lion King (right down to "Just Can't Wait to be King" taking place a day after "Circle of Life").
Anyone else notice how uncannily similar Timon's "That's All I Need" sounds like the Broadway Musical's "Warthog Rhapsody"? That song was about Timon and Pumbaa being happy with what they have, and this one is Timon singing about what he wants. Ironic.
Timon and Pumbaa show up in a lot of scenes from the first movie, adding humor to them. Despite being in the wildebeast scene though, they never see Simba, Mufasa, Zazu, or Scar. Why? Two reasons.
Continuity-wise, it'd be jarring if they saw young Simba, then didn't recognize him when they properly met, plus realistically, they're probably too far away.
Mood-wise, they didn't want to ruin one of Disney's most tragic deaths by putting a comedy duo in there. The rest of the scenes they do get involved in usually have room for comedy. Scar's Villain Song is chilling, but it's also hammy and Scar's a snarker. Heartwarming moments (Simba's coronation or Simba and Nala's love song) and awesome fight scenes (The final battle and Mufasa rushing to save Simba and Nala) usually have room in them for funny moments, maybe to lighten the tension, that's what Timon and Pumbaa did in the original film's final battle. Timon celebrating Simba and Nala's fallout isn't really played for laughs, it's a melancholic Dramatic Irony, and Timon thinking Scar and Simba are talking things out when Simba was really just learning that Scar killed Mufasa is also irony, but less sad and more amusing. For similar reasons, Timon and Pumbaa leave just as Mufasa begins to appear in the clouds for his dramatic scene with Simba.
What became of Pumbaa's family? Given his isolated background, could be possible that his family abandoned him because of his smell? Leaving him in a world where he could be killed?
Adult male warthogs generally live alone. And this is why.
Hyenas are known to eat meerkats (face it; everything eats meerkats; they're nature's buffet table) and Timon's father is missing. Let that thought sink in.
Assuming the "Uncle" isn't just honorific, Uncle Max could very well have been Timon's father's brother. If the above horror is accurate, Max had one more very good reason to be unhappy with Timon's carelessness on guard duty.
Most bottom-of-the-food-chain animals are Explosive Breeders to some degree, due to the fact that most of them get eaten anyway, so popping out a ton of babies is necessary to ensure at least some of them survive by sheer chance. Meerkats might not be on the level of rabbits, but the size of Timon's clan despite meerkats being "nature's buffet table" indicates a decent repopulation rate. Now what happens when you take a fast-breeding prey animal and put it in an environment with none of its predators? The population grows out of control and they eventually end up eating all of their food faster than it can replenish, while choking out native animals dependent on the same food. While the prior food chain of their new home seemed to end at "bugs" prior to Timon and Pumbaa and later Simba(I don't remember if we saw birds apart from the vultures, but there definitely weren't any other mammals if memory serves), and they alone didn't have that much of an impact, the whole meerkat clan might gobble up their new home in a matter of years.
Fortunately, very few individuals actually breed in a meerkat colony, the vast majority of the clan aren't going to be reproducing. Also, the jungle was quite big - if food runs out in the part they're currently living in, they can just move to another part of the jungle until the insect population recovers.
In this movie Timon and Pumbaa only find their jungle after the wildebeest stampede, and a musical montage implies they spend quite some time there before they find Simba (as there are alternating day and night scenes). Which means Simba has been wandering in the desert for several days after his father's death.
