Don't know your full needs, so I'm assuming the highlighted notes indicate a well thought out design.
I like most of your conventions, but I'd avoid using camel case for column names for foreign keys and use tablename_columname (i.e. user_id, brand_id, etc...)
If all brands have a category, I'd kill the connection from brand to model. Do all brands have a category? If no, then you're stuck with both foreign keys.
If all models have at least one meta, you can lose the type foriegn key in the model table. You then could also drop the brand foriegn key in the model class as well as the country