Re: many happy returns of the day or many more happy returns of the day
The only time I can imagine seeing this would be on a Facebook page. If it were someone's birthday and lots of people had posted "Many happy returns of the day", it's just possible that people going on there later in the day might add "And here are many more happy returns of the day from me!"
However, in general everyday use, we do not use the word "more" in the phrase.
Remember - correct capitalisation, punctuation and spacing make posts much easier to read.