Welcome to cruise-chat TLC. I've not cruised on Louis Cruise Lines, so do not know what their attire is. All of the lines we've been on have had the buffet option, which is not formal. We've only sailed on Norweigan Caribbean, Costa, Royal Caribbean, Holland American, Carnival, and Princess. Princess is my favorite, so far, but that is only my opinion. If you have a travel agent, that specializes in cruises, that would probably be your best avenue for advice. Cruise specialists can match your requirements to the best fit. You are in for a wonderful experience, but be aware, cruising is addictive
I'm sure there will be others to help you on this board as well. Best wishes!