Well yeah you can make a simple fall damage based farm for most of the mobs(except iron golem, blazes etc) and connect them with Mob Drop Hoppers or Mob Drop Chest(a special type of Hoppers and chests available in /shop under redstone category) .
However, mob farms on Skyblock Dream don't really work well unless you are famous/have a lot of island members/your island is in top 20, cuz mobs won't spawn unless a player is present on the island and will despawn if no one is present.
Hope this helps.
Regards