Hi Imkay, welcome to the forum.
So you have visited Morocco twice now? The first was to meet your future husband and have an engagement celebration, then the second was to get legally married? When will you have your wedding celebration? It is very good that you did not marry during the first visit because it causes a major red flag.
Well I can only speak from my experience and I don't want to scare you but Rabat is one of the most difficult offices to go through due to marriage fraud. When my husband and I sent in our proof of relationship, we sent in absolutely everything we could think of ... phone bills, facebook, msn, skype, tons of photos of us traveling with his family or visiting family and friends, receipts from our travels (i had visited him 4 times by the the time we submitted our application and already had a ticket for the fifth visit) .. the receipts included hotel receipts, gas receipts, restaurant receipts, gift receipts, etc, etc. We literally submitted an entire box of proof. We did as much as we could because we had the usual red flags (age difference, culture/religious difference). Our major red flag was that we did not have a wedding celebration/ceremony. I know some of the VO's tend to focus on this as being very important but I guess it depends on the conduct of the relationship. I think it helped that when we submitted the photos, we had a lot of pictures of many people (family & friends). Also time was on our side. We met in 2009, I visited him September 2010 and then returned to marry in July 2011. We didn't submit our application until 2013 (I don't know if this was a good thing or not ... lol)
So like I said, we submitted so much proof. Later when we ordered our GCMS notes, they noted that our file was well documented. Even at the interview, the VO told my husband that we have much proof and that this is an advantage for us. After the interview, the VO told my husband that he would approve our application and he gave him back all our proofs. I had organized the proof very well, included a table of contents, etc ... and we could see that they did look through our proofs but didn't read everything because some of the envelopes were opened in a way that you can tell they just peaked inside.
So when submitting your proof of relationship, take into consideration the concerns a VO might have. I can see you have a couple of things going for you already, which is no big age difference and you married on your second visit. Do you follow the same religion? If yes, then that is a very good advantage for you. If not, then you want to make it clear that you and your husband have discussed which religion your children will be raised by. Also, when will you have your wedding celebration? Like Habeeb said, they do tend to put an importance on this. I don't know if my husband and I were just lucky we were approved without a wedding celebration. Maybe because we took a very long honeymoon, it helped in our favour. If you plan on submitting your application before your wedding celebration, be sure to include proof that you are indeed planning on having on. Also you mention that you have a child from a previous relationship ... be sure that your husband knows about almost everything about your child.
Good luck to you and your husband! This process is a long one but definitely worth it in the end!!