Sorry for the confusion.
Yup, that house rule would work fine, but I'd still recomend you take a look at the new profiles, some are quite nice, some are not so nice
Only good can ally with good, and bad with bad, so you can't bring in warg riders for your womt :p Just meant any good with any good, etc.
For your edit, pretty much. So an example army would be gondor capitain and 12 womt, faramir on horse and 12 knights of gondor, and eomer and 12 rider of rohan.
Your also supposed to have a "leader" but there was no rules explaining the significance of that, so it was a moot point. Oh, and hero's like the twins or kings champ where you buy them together are placed in the same warband, so you can't lead multiple warbands with them. Makes sense.