[name]Hi[/name]! I’m not terribly keen about nicknames as first names for girls – women have a hard enough time in the professional environment without having to deal with a diminutive (which means “small, tiny, triviality”) for a name.
HOWEVER! I love [name]Hallie[/name], which has the -ie ending.
From my research, it is not a formal nn for anything. It stands on its own, though it is related to [name]Harold[/name]/[name]Hal[/name]. So my suggestion is just to stick with [name]Hallie[/name], as it is a full name. It’s not like calling a daughter [name]Ellie[/name], where it is obviously short for something. If you MUST have a longer name, here are some options that contain [name]HAL[/name]:
Halycon
[name]Cathaleen[/name]
[name]Athalia[/name]
[name]Halda[/name]
[name]Hala[/name]
[name]Halina[/name]
Haloma
[name]Mahala[/name]
Go to super search and search girl names containing hal for the full list