The emoji thing is true. If you are overdoing it in your ad you will get rejected. This aspect is categorized as "circumventing systems"
Did you ever got rejected? I'm doing FB advertising full time for years, using emojis for my campaigns and all the clients, and never ever had a problem. The theory is one thing, actual practice is something completely else.
There are a thousand rules, that you can interpret as you wish. Another one is never using 'YOU' in the ad - which is not true. You can use 'you/your' easily as a question. The reason they have this 'rule' is people claiming to make them money/lose weight - 'We will make YOU money...' type of copy.