I don't think model space will be an issue. who knows, maybe BI will increase number of models? Anyway, with vikings and gaels sharing lots of units, I doubt it will be a problem. One thing to remember is that a faction with a lots of horses needs different models for each horse. Off topic here though. When looking beyond the maximum number of models, the problem disappears totally with 500 max.

I vote native names. By the way, the native name for swedish nobles is actually "skinkerytter"