[1.11.2] Creating Ranged Mobs and Mounting Mobs on Horses

Hello, I'm current Attempting to implement 2 new mob types, one of which I'm planning to have mounted on a horse, and the other a ranged attacker.. 

Archer Villager

public class EntityVillagerArcher extends EntityVillagerSoldier implements IRangedAttackMob{

Horse Mounted Villager:

public class EntityVillagerCaptain extends EntityVillagerSoldier{

Completed Melee Villager:

public class EntityVillagerSoldier extends EntityVillager{

On the topic of the horse mounted Villager

I've attempted to copy some code from the spider class replacing the spider references with a new horse, but all it does is freeze my EntityVillagerCaptain once it's spawned. 

 EntityHorse horse = new EntityHorse(this.world);
	        horse.setPosition(this.posX, this.posY, this.posZ);
	        this.world.spawnEntity(horse);
	        this.startRiding(horse);

Some Notes:

The EntityVillagerCaptain jerks his arms and legs around rapidly.

The horse is nowhere to be seen.

And upon some debugging, the message:

[16:42:28] [Client thread/WARN]: Received passengers for unknown entity

IS also displayed in the console each to a EntityVillagerCaptain is spawned.

Is there something I'm doing wrong, or is there a better way to do this?

On the topic of the Archer Villager

My main problem is that the EntityAIAttackRangedBow requires the class to be an instance of the Abstract Skeleton Class .

However I can't make my Archers extend this class as my villager soldiers will start attacking them.

EntityAIAttackRangedBow(AbstractSkeleton skeleton, double speedAmplifier, int delay, float maxDistance)

Should I just make my own custom AI? or is there a workaround to my current problem with Villager Archer?

Thanks.