Okay, so since it's homestuck, I would recommend overly complicated, inconsistent mechanics. Ordinarily, this is stupid, but if you're going Homestuck, you need to go wacky. For instance, tasks might be accomplished by the roll of a die. Say, a d20 with a target number (arbitrary example). Special powers can be used by playing various cards, some of which are modular (allowing or requiring you to play them with other cards at the same time). Many will modify your die rolls (whether by adding a modifier, extra dice, or giving you a dice pool, or whatever else you can think of), and others will grant you special actions that you just couldn't otherwise take.
Each class and aspect comes with certain cards, which are shuffled together into a player's deck. At the beginning of each narrative turn, which may be a distinct category from combat turns, a player may draw a card either from their deck, or a shared Skaia deck, which is mostly Weird Time Shit, plus several cards that add new rules to the game (for instance, the Green Sun, or Trickster Mode). Each of these special rulesets comes with their own deck of cards, one card from which is played every turn the decks are in play. Many should require increasingly bizarre mechanics - for instance, if God Tiers are out, you might need to get a particular score in a game of darts in order to determine whether your death was just or heroic, but a variety of other powers (for instance, Light powers) can let you alter your effective score.
Maintaining balance will be difficult, to say the least. At any rate, this is all off the top of my head. I wouldn't recommend actually using it. It's more an example of how inane your rules should wind up being, if you want to capture that genuine Homestuck feeling. The whole thing should wind up feeling like a game of Calvinball.