Strategical page structure questions

Hi there, I am setting up a multi language page and have a question regarding taxonomy
and site structure in general:

I want to have something like this:

global pages like /contact and /about us in different languages without taxonomy.
--> done

Content pages like /blog or /othercontenttypes in all of the languages. All of them should be
connected to the one taxonomy. (e.g. for dogs or cats)

The user can choose his topic (e.g. cats) and gets all content types with only cat related information.

So, I set up taxonomy 'cats' and 'dogs'. I set up taxonomy, lets say 'parts'. I created a
taxonomy menu (submenu) for the content type /blog out of the 'parts' taxonomy. So taxonomy for /blog is
first: 'cats' or 'dogs'
and second: 'parts'
at the same time.

I don't get the main information 'cats' or 'dogs' into the url. I only get the second vocabulary
information in the url and I don' t know why and how to change this. (already set up 'primary term module'
but it is not helping)
My question is now: How can I handle that when 'cats' is chosen only cat related entries show up in
the blog submenu and in other content types and how can I get it into the url?

Without the 'cats' or 'dogs' distinction in in the url I can not filter content and blog entries for both topics
show up. Am I doing this right or is there another solution setting this up?

I hope this is somehow understandable and thanks for your answers, I am confused at the moment!