[name_f]Every[/name_f] name you listed is a valid option. There’s [name_f]Lulu[/name_f] as well.
I wouldn’t worry much about nicknames they develop over time, naturally. This is especially true with a name like [name_f]Luella[/name_f] where the nickname options are all great.
From the poll, my favorites are [name_f]Lu[/name_f]/[name_u]Lou[/name_u] and [name_f]Ellie[/name_f]. [name_f]My[/name_f] personal favorite is [name_f]Lulu[/name_f]. I kind of like [name_f]Lula[/name_f] too.
I voted for [name_u]Lou[/name_u] and [name_f]Ella[/name_f], as I feel that they are more intuitive. However, I also would’ve voted on other if I had seen it before voting as I think [name_f]Lula[/name_f] would make a sweet nickname for [name_f]Luella[/name_f].