Marabelle
We really love this name and are set on it but I am hoping others can think of nicknames that I haven’t thought of. I tend to prefer nicknames ending in -ie -y sounds but not sure about Mari or Mary. Also not sure I love Mara as a nickname.
I do plan to use Mare Bear and Ma Belle (we are bilingual en/fr)
Anyway hoping other minds have other suggestions 
Eta brothers name is Théodore and Teddy for short
I’m thinking [name_f]Marlie[/name_f] / [name_f]Marly[/name_f] or [name_f]Mimi[/name_f]!
love these ideas!
A few other ideas:
[name_f]Abbie[/name_f] (from [name_f]Mar[/name_f]abelle)
[name_f]Ellie[/name_f] (from Marabelle)
[name_f]Mallie[/name_f] (from Marabelle)
[name_f]Bebe[/name_f] (from [name_f]Mara[/name_f]belle)
[name_f]Mamie[/name_f] (a nickname from Mary)
[name_f]Mitzi[/name_f] (from Mary)
I love the suggestion of [name_f]Marlie[/name_f] … I was going to suggest that too. Other suggestions:
[name_f]Mar[/name_f]
[name_f]Belle[/name_f]
[name_f]Ellie[/name_f]
[name_f]Ella[/name_f]
[name_f]Elle[/name_f] / [name_f]El[/name_f]
[name_m]Abi[/name_m]
I think [name_f]Marie[/name_f] or [name_f]Ellie[/name_f] would both work well as [name_f]Marabelle[/name_f] nicknames.
I like Emmy… especially if she has an E middle (like the initials ME). [name_f]Molly[/name_f], [name_f]Mellie[/name_f], Bellie, [name_f]Ellie[/name_f], [name_m]Arie[/name_m], etc. might be fun. I also like [name_f]Malou[/name_f] but that doesn’t end in -ie.
Good luck!
[name_f]Mabli[/name_f]
[name_m]Ari[/name_m]
[name_f]Maisie[/name_f]