The path will depend on if these are paid or unpaid internships: if paid, then the J-1 visa is probably the best option; if unpaid, then the B-1 business visitor visa is an option. For the J-1, there's really no need for a lawyer to execute the application, just to provide advice at the outset; for the B-1, I would recommend getting legal advice and support but this won't be expensive at all.