dun, No need to hire a lwawyer, If he or she is legal here in US, when you get first letter they will ask you where u want to go for an interview, You can choose Nepal or canada whichever you want to just follow the procedure i.e make the police report for both of them from place where they have stayed after 18 the birth day, Bank statement depends on sponsor letter. Some says no need ot sponsor letter but i don't trust none of them, I will find a sponsor, since they are staying here and I don't see anything hard for them to get Sponsor letter .Its very simple and to the point. But if they are illegal then my suggestion is to hire a lawyer. Hope this helps