Help with Adoption vs Guardianship

My friend's adult niece got pregnant and wants my friend and husband to adopt her baby. They agreed to adopt her baby while she was still pregnant. However, my friend and I aren't seeing eye to eye on this situation. Her niece lives with them and they are all very close. This arrangement will continue after the baby is born. They met with an attorney who told them to come back when in the 3rd trimester. They didn't and figured they'd start the process after the fact. So now the baby is here. My friend and her husband are filing for guardianship -vs- seeing the attorney to start the adoption process. They are filing the guardianship paperwork themselves. I do understand that guardianship is easier at this point, however, still a lot of paperwork and if they don't file the follow up forms, their guardianship can be revoked. With all that being said, wouldn't it be easier for them to start the adoption process with the attorney, file Change of Custody paperwork and go from there? I feel as if my friends are wasting a lot of additional time and money with the guardianship process, considering the process can take up to 4 months, then pushing off the adoption process even further. From what I've read, you can't start the adoption process while the guardianship case is still pending in court. Other than cutting corners with cost, etc. what is the benefit of obtaining guardianship instead of the attorney starting the adoption process? Thank you in advance.