The Pebble and the Penguin/WMG

Herkermer Hormolka from Congo and Drake are incarnations of the same Time Lord

Herkermer was first. After being killed by the gorillas, he had insane rage, and vented it out. That is why Drake is the main villain.

Similar to the above WMG, Mickey Mouse and Hubie are reincarnations of the same Time Lord

The laughter was not a coincidence. Hubie is Mickey Mouse reincarnated.

The pebble was what enabled Rocko to fly.

When Hubie made his wish, he wished at /that moment/ to find the perfect pebble, which is why the wish came true in the form of a pebble. But the pebble came down to earth as a star falling- meaning the pebble essentially was the star he had wished on. What he really wanted, most of all, was to win Marina's heart. Drake shoved Hubie off the ice while trying to get his pebble, with the side effect that Hubie plunged to the seal-infested waters. Drake was perfectly happy with this. However, if Drake hadn't done that Hubie never would have gotten taken onto the Good Ship Misery or met Rocko. If he hadn't met Rocko he never would have learned to fight or to have confidence, which means that if the whole adventure hadn't happened Hubie probably would have wound up killed by Drake anyway. Eventually Hubie lost the pebble and Rocko got it for him, but Rocko had it for a while before he could give it back to Hubie. I don't think Rocko ever flew before the first scene he's shown flying in. I think that as he was diving, he wished with all his heart that he could fly- as he's obviously done many times before- and because he had the 'star' with him, it granted his wish.