For historical reasons, the laws of the State of Louisiana are partly based on the Civil Law of France and Spain rather than on the common law of England.
In any event, obtaining a visa to work as a lawyer in the US is not straightforward.
As for the work done by barristers and solicitors, the summary above is in broad terms correct but there is more to the work of a barrister than appearing in court. Most barristers are consultant litigators, who as well as arguing cases in court also draft court documents, advise on substantive and procedural legal issues, and advise on litigation strategy and tactics.
In the US, and other jurisdictions, the legal profession is fused, although in practice some US attorneys do work like that of an English solicitor, and some work more like barristers. Star trial lawyers in the US are sometimes instructed by other lawyers, much like barristers in England.