Ohsolovely

Sometimes, the Consulate Officers ask about wedding plans.........Just remember.....It's entirely what the consulate officer thinks that matters.......Good luck in your endeavor.

According to internet engagement party (in Ghana)  women and you would be in one room and men in another
any time the 2 of you are together (in matching dress)  and have been introduced to family with all the traditional gift giving,  you are married

This - we weren’t denied but were given a hard time at our adjustment of status interview when they saw a photo of us at someone else’s wedding (his fathers) I had to offer to get the wedding certificate to show he had been a witness to his fathers wedding. I wasn’t even wearing a dress in the photo just a nice top I wear for work. 
 
They also somehow found a photo of him with his half brother (we didn’t give it to them) and began to think he had a kid with someone else. Asked about three or four times about him having a kid. So they do research other than what you give them and you can’t control what people you know put in the internet. 
 
So you can see how even without any real basis they can pursue you and you are intending on giving them an actual reason to deny (yes they can do this at a later immigration stage if they find out about anything that wasn’t supposed to happen occurring). Some people have had their citizenship denied and sent to an immigration judge because something was amiss with the initial visa given. 

I am so sorry you are going through this. I know your pain, because I was in your position a couple of years ago. We didn't do the traditional engagement ceremony. But we did have a party where we wore matching clothing. My husband...then fiance took pictures from this to the interview and we were denied for the same reason. It has happened to many people on this site. The reason they don't allow people to go through the K1 with an engagement party is because they accept that as a marriage for the CR1 visa. Therefore they can't allow one couple to say they aren't married, but another to say they are after having those ceremonies. I hope that makes sense. 
 
The good news is you can start over and get approved. I traveled to Ghana, got married after our K1 was denied and started all over. My husband arrived in 2017 and we just welcomed our first child. 
 
The best thing you can do is get married and apply again. You'll want to include plenty of solid evidence with your initial petition, including trip evidence, chats/call logs, letters of support from your fiance's family and friends, bills if they can add you to them, etc. Keep in mind you'll need much more quality evidence to be successful getting through the Ghana embassy than people need at other embassies. You can look at my review of my husband's interview in my timeline. I listed out everything we submitted at all three phases. I am not saying you need all of it, but it will give you some ideas of things to submit.  

For what it's worth, I spoke with an immigration attorney after our K1 visa was denied. She recommended we not include any photos from the engagement party because it would draw attention to the reason our K1 was denied. We followed her advice and the CO never brought it up during the CR1 interview.