I think it would be fine. There are parents and children with the same name after all! [name_f]My[/name_f] cousins also have rhyming nicknames and it kind of works [name_f][/name_f]- and I’ve been in plenty of situations (largely at work/school/uni) where you end up with a group with an [name_f]Ella[/name_f], a [name_f]Bella[/name_f], a [name_f]Daisy[/name_f], a [name_f]Maisy[/name_f], an [name_f]Eva[/name_f] and an [name_f]Ava[/name_f]? 
[name_m]You[/name_m] might also find that if [name_f]Elara[/name_f] becomes ‘El’, you might get called ‘Bell’ less when she’s around, if that makes sense?