Advice for rpg-like survival server

I have an SMP server, but I want to add some elements to it that are very hypixel skyblock-y. Custom items, armor, the auto compactor, an auction house, and custom retextured mobs (like stronger blazes) that can be made into custom spawners. I dont really need anything else. whats the best way to go about doing this? (once again, using absolutely zero actual sky islands)