We have a client, presently a citizen of Venezuela. He has applied for
U.S./Puerto Rico citizenship, and is waiting and working on that process.
He resides in Puerto Rico (over 2 years), and is treated as a Puerto Rico
resident for tax purposes. He is the sole owner of an LLC (disregarded
entity, he files Sch C) that is a member of a Fl LLC, located in florida. He
does work for business in its Puerto Rico office. The LLC is profitable,
and he draws a salary from the LLC as well. Thus, I believe he is paying
Puerto Rico taxes on his salary, and U.S. taxes on his share of the LLC
profits.

In order to deduct contributions to the LLC plan he needs to have US compensation, not dividend income from the LLC.

would all LLC income be considered dividend income? i know it would get reported on a K1.

You have to talk to his accountant to see how the LLC income is reported.