I plan to download and start going through the plugins tonight to ensure the work on the Production server, and then going through the configuration and setting up the "Adventure World."
I don't know if it helps, but in the case of the Dynamo Command Block Creation, all the new "mobs" were repurposed old mobs and their existing AI. Colored leather armor changed the appearance along with player heads and renaming. I believe the spawners created the mobs with a few enhanced changes, but "scripting" the mobs, as such, simply wasn't possible. Thus a Zombie Pigman in brown leather with a "bull" player head became a Minotaur complete with leather and steak drops, and they were spawned with axes in an already aggressive state to attack any approaching player. Beyond changing the name, skins, aggro state and drops, Zombie Pigman.
The "Ice Blaze" were ordinary blaze spawning from an ice tower. They couldn't be colored or have their appearance altered, but with a name change, their "Ice Tower" home and drop of packed ice rather than blaze rods, they were "Ice Blaze" and nobody gave it any further thought.
Zombies in green leather armor, sunflower heads, "Sunflower Monsters", or something like that. I really can't recall what they were called. So they were really "zombies", but nobody cared. They were still fun to fight, and because they had "helmets" they were just fine in daylight.
I don't know how much you can do the same with your scripting, or generate "tweaked" spawners that produce "custom" mobs with ordinary mob AI. Or maybe doing something like this is what causes the massive scripting headaches. I really don't know what is going on "under the hood", at least I won't know until I start picking through the configuration and proofing the scripts. But sometimes "less is more." If you can save scripting effort, memory space, and general lagginess by putting clown suits on zombies but otherwise leaving them untouched... Killer Clowns it is, and I see no reason to give it a second thought.
The part to give thought to would be the structure they come from, their drops, and "why they are there." Companion mobs that fit the theme, ways to make them more scary, theme fitting traps, and so on. What "story" do you tell with the mobs and their structure? It doesn't even have to be much of a story at all, just that the player encounters a brightly decorated tent, and HOLY HELL! KILLER CLOWNS! Or... something. Scripting special AI behavior seems like a lot of effort for not much gain. This would be especially true if you can use stock AI behavior in a carefully prepared structure to let the Stock AI shine. Snocrash made an "AFK Gold/XP Farm" seen here: https://www.youtube.com/watch?v=jQWG9Q7HoUA It simply tricks stock AI. I am not suggesting you build an Easy AFK farm, that isn't the point of the structures or this particular map. But if players had to fight hordes of mobs that were coming at them in specific ways because of the structure design and their stock AI, it could be "interesting."
The only downside is that Mojang "tweaks" to the AI would cause these to fail, as has happened with Snocrash's farm on several occasions. But hopefully this is a start in a better direction.
Now on to poking through the Alpha package...