I found nearly 600 girl names beginning with ‘al’ in the search form, picking names not already suggested (I think).
[name]Alanna[/name] - mentioned in description that it seems less of a feminization of [name]Alan[/name] than [name]Alana[/name], but this is a variation of [name]Alana[/name] with one n, I just like two.
[name]Alessia[/name] (Italian form of [name]Alexis[/name])
[name]Aloisa[/name] ([name]German[/name] variation of [name]Louise[/name])
[name]Aluisa[/name] (Spanish variation of [name]Louise[/name])
There were so many versions of [name]Alexis[/name]/[name]Alexandra[/name] and [name]Alice[/name]/[name]Alison[/name], as well as many names that are supposed to start with E, like Aleonor or [name]Alizabeth[/name] and any possible variation of either (dozens upon dozens of that sort), and also a lot of place names, which always seem weird to me if the location is not significant to the family. I think if you try search or direct your sister to the site, it doesn’t take too long to look at the pages and eliminate a lot, but dig up some that you might like better than were already suggested.
I also tried search on names that end in ali, aly, ally, and alia, but I thought that most were kind of a stretch. Try that though, it might turn up something meaningful for you. As yet, it seems impossible to search on names that might contain the trio, ‘ali’ to get the nickname from the middle - I think it’s sort of a stretch to do that anyway. I think I suggested the name [name]Mahalia[/name] to someone yesterday for example. I might call [name]Mahalia[/name], [name]Ali[/name] for a nickname, but not, say, [name]Natalia[/name]. You can name the kid [name]Francesca[/name] or something, and still call her [name]Ali[/name] around the house, it’s not unheard of for nicknames to be unrelated to the formal name or to be derived from a middle name instead.