Grandparent Names

I'm having some trouble with what grandparents want to be called. This is the first grandbaby on both my side and my husband's side of the family. My step-mom and dad have picked out names (Nonni and Poppy), my mom and step-dad say they have time to come up with something because he won't be talking for a while anyway (very true statement), and my mother-in-law is convinced she will be called Little Mama. 😐 My father-in-law's comment on the situation was that he just had a list of things he didn't want to be called. (He once said a few years ago that he'd like to be Big Daddy, but other than that he's not shown much interest in the topic.) My mother-in-law is insistent on Little Mama, but it makes me very uncomfortable. She's very "maternal" and is obsessed with "being the mama". She has two sons, and is pretty in their business, so I'm just concerned that she's not sure how to differentiate between mom and grandmother, and having my child call her "Little Mama" just really makes me burn up inside. I just need some advice!