hi
if you are using mult-site and each sub-domain is a language it should not be to difficult.
you probably do not need the extra menu and this is complicating it.
try a single menu and for each page allocate it to a specific sub-domain user, this will determine which sub-domain it will display on.
be cautious how you use featured article.
there is some info in v2 which is shown above and this is very useful.
you are also restricted in the amount of sub-domains you can have - see v2 forum and do search of v3 forum.
cheers.