>> If I use it only as a verb can I write {tlhIHchuq SunovchoH} ?

> No.  I can't imagine what a type 1 verb suffix on a pronoun as "to be" might mean.

>  "You are each other"?  Even if so, how would it relate to the second sentence?

>  "You are each other you begin to be foreigners."  Why not, {SuSovchuqchoH}?

HIvqa' veqlargh!  Obviously I meant, {SuSovbe'chuqchoH}.