How to get 1.2 working on BI engine

[Ludens]

However non of my units have the ability to swim. I'm also not sure about the shield wall, and what is hoarding? I've never heard of this aspect of BI.

Since these abilities are not present in R:TW 1.5, no units have been given them. You need to mod them in yourself. Hording (and not hoarding) means that a faction will gain a large "horde" army when their last settlement is conquered. They can use this army to reestablish themselves elsewhere. Again, this has to be added manually since it is not present in EB.

[Maion Maroneios]

Yeah, especially hording requires quite a few manual changes so I recommend you just stick without it, as it may cause problems. Even I don't have a clear idea as to how I did it myself!

Maion