Hmmm these don’t have an particular significance but I think they’d be cute
[name_u]Nori[/name_u]
[name_u]Berry[/name_u]
[name_u]Bo[/name_u]
Lemmy/Lenny
[name_f]Dori[/name_f]/Dory
[name_f]Dee[/name_f]
[name_u]Mo[/name_u]
[name_u]Rory[/name_u]
[name_u]Remy[/name_u]
I’m sorry it’s been such a stressor coming up with a name!
I’m wondering… as some mentioned above, kids generally start giving parents names that come with the first sounds that they say, like mama, papa, and dada, and then mommy, daddy, papí, but as they get older, many transition their parent’s name to something else, like mom, dad, mother, father, pops, first names, etc.
Would one option for finding the name be to work backwards? Thinking about some of the baby’s first sounds and patterns they’ll be developing, what would be a good “baby friendly” name for their parent? Then the official name can evolve from that, either now before the baby is here, or years from now with the kid’s input, family memories, and natural progression of the first name all able to influence it.
Best of luck to y’all!
Oh! And I wouldn’t worry all too much about it being too close to your sister’s nickname. Mommy sounds like [name_m]Tommy[/name_m] and Daddy sounds like [name_f]Patty[/name_f], but nieces and nephews don’t even realize they are similar because they always put “aunt” or “uncle” in front of it. I know that there is extra consideration here, and mommy and daddy are more well established names, but if that’s the name yall like best, then it might be worth keeping on the list
[name_f]My[/name_f] wife and I are both cis women and use she/her pronouns … We’re planning to use Mum/Mummy and Mama. Not sure who will be who yet. Very similar but we’re both attached to these names. It’s very possible that the child will end up picking for us lol!
So many great suggestions here. I noticed you listed [name_f]Mimi[/name_f] as an option but didn’t mention any particular issues as with the others. I really like [name_f]Mimi[/name_f]! Also Maddy. I don’t think it’s a problem that they can be given names too.
I like the suggestion of taking a sound or letter from your partner’s name … [name_f]Essie[/name_f], [name_u]Essa[/name_u], [name_f]Ettie[/name_f], [name_f]Etta[/name_f], [name_f]Sasa[/name_f]?
I also like what @eattacosforbreakfast says about “working backwards”. [name_f]My[/name_f] wife’s grandmother goes by [name_f]Minna[/name_f] to her grandchildren and great grandchildren … This name evolved from one of her grandchildren mispronouncing her chosen grandparent name at the time, and it stuck!
Good luck, I’ve no doubt you’ll both come upon the right name soon. 
I think [name_f]Essie[/name_f] could be great, given SO’s name.
I think this is a super fantastic suggestion, and will totally talk to SO about it!
They recently brought me the first suggestion they’ve come up with, which is [name_f]Oba[/name_f]. I thought it was interesting that it is used to mean “aunt” or “grandmother” in Japanese, which SO was not aware of when they came up with it. If we used your suggestion, @eattacosforbreakfast, that would put [name_f]Baba[/name_f] back on the table. Definitely some food for thought here!
Thank you so much for everyone who continues to offer feedback and suggestions. I feel very supported by y’all. 
Baba means dad in my language, my 8 month old brother can say it perfectly so I support that idea 
Similarly to [name_f]Baba[/name_f], [name_m]Abba[/name_m] is an option that in some languages means parent or father. [name_m]Even[/name_m] if it has masc origins I think a lot of people in [name_f]English[/name_f] speaking places wouldn’t associate it with either gender. And it’s also easy for a little sproglet to say. Best of luck!
My spouse is non binary and our kids call them [name_f]Pippa[/name_f], it’s what was easiest for us, we had a 7 year old, a 3 year old and two 1 year olds when they came out so the transition from Papa to [name_f]Pippa[/name_f] was best for the kids as well.
My spouse has said that if they had been more sure of their identity before we began having children they would probably have picked a more feminine leaning parent name ([name_f]Mimi[/name_f], [name_f]Momo[/name_f] or [name_m]Mosie[/name_m] for example), but they’re happy being [name_f]Pippa[/name_f] as well!
I know a couple that are mama and mapa to their kiddo 
Thank you, everyone, for the amazing replies, and the amount of support you’ve shown for myself and partner (surprise, @lavenderwitch, I’m in your forum, posting on stuff XD).
I’m kinda low-key opposed to the “P” sound names, because part of the issue is other adults hearing the child, and making assumptions because the name invariably mutates into something that barely resembles the original.
We’re currently rolling around “[name_f]Oba[/name_f]” as the word, to see if it feels right, but I’ve got to admit it’s not…really hitting my “what I want my child to call me for their growing-up memories”, and intersecting with the word for “Grandparent” is an additional side-concern.
I really like the suggestion of [name_m]Abba[/name_m]. It’s very parental where I’m from, and it’s easily one of baby’s first words.
Ooh, I never even thought of this before…
Seeing their name, maybe Sa? Where I’m from it isn’t uncommon for parents to go by Ma or Pa. Sorry I can’t give any other suggestions but I hope you are able to find something that brings you joy. Congrats!
…hadn’t thought of a shortened form of my own moniker, thanks for that.
(Unfortunately, “[name_m]Abba[/name_m]” not an option for us due to the…patriarchal religious contexts which use that name to refer to the primary deity as an overtly father figure.)
I’m curious if there’s a list of the easiest sounds for a child to make floating around here somewhere.
@tessallation This is an Australian/English language resource only but it’s quite thorough I think: Speech Sounds Development Chart - Kid Sense Child Development
Oh wow. Everyone’s suggestions are just amazing. I was reading through thinking about my favorites, even though it doesn’t apply to my family. I loved renny for parent and [name_f]Maddy[/name_f]. They’re so cute and would grow well into the child becoming and adult.
I wanted to add that my first son called me [name_f]Emma[/name_f] for about a year, for no reason really. He just got the word “mama” a bit jumbled and stayed with it. Whatever you choose will be perfect and meaningful. Congratulations 
Sorry to double post but I just remembered another example that might help. [name_f]My[/name_f] little cousin always said “mao-wam” as a baby instead of Mum. They decided to go with it. He’s 10 now and still calls her Wam, or WamWam. Pretty cute right?
Also, I don’t know if this has been said before but the consonants in order of difficulty tend to go:
B, M, P, D, T, N, G, K, W, H, F, V, Th, S, Z, L and R.
So for example something like Memma, [name_f]Gigi[/name_f] or Neenee would probably be easier than [name_f]Zazu[/name_f], [name_f]Leelee[/name_f] or Rara. I really don’t think this should dictate the whole search because all children learn at different paces anyway but maybe it’s useful to know.
Good luck with your search!
I know a few non-binary parents and they struggled with parent names too.
Here’s what some of them settled on:
[name_u]Ren[/name_u]/Renny (short for parent - this is a pretty common one!)
Appa and Oogi (they’re both non-binary and chose the names of the flying bison from Avatar: the Last Airbender, lol)
[name_f]Mimi[/name_f] (but I know you’ve already ruled it out)
[name_m]Obi[/name_m] (pretty sure this is parent in some other language?)
Those are all of the ones I know, but I also think [name_f]Momo[/name_f] could work. It’s super cute and reminds me of Mama.
Makua is Hawaiian.
Dodi/Dody/Dodie might be an option. It’s used as a name for both males and females, but is most commonly a more feminine nickname, it has similar vibes to Mommy and Daddy, and should be pretty easy for a little one to say.