Verified answer

There is a popular phrase "よろしくお願いします" and its shorten version "よろしく". They have a wide variety of meanings, such as "Thanks in advance, "Nice to meet you", "I appreciate your attention" "Sincerely yours", etc. In short, they are phrases to express gratitude and show sincerity.

When someone tell you "これからもよろしくお願いします" at the end of a conversation or a letter, it is a polite and nice way to say "Good bye".

"ヨロシクさん" is not a common phrase. It is a sort of words play. This "さん" is a honorific like "さま" or "くん", but meaningless. It makes this sentence more familiar.

これからもよろしくお願いします > polite, formal, allowed to use for your superiors

これからもヨロシクさんです > informal, familiar, funny, allowed to use for your superiors or strangers

Edit.

Yes. Usually, "さん" is used only for people, so "ヨロシクさん" sounds like "Mr. Hello" in English.