I'm not keen on Isla Hall sorry to say, it seems bland
Also, for some reason when I read it quickly to myself it sounds like 'i'll call'
Maybe that's just me thinking that though!
How about Emilia Rae, Lucy Rae, Lexie Rae, Sophie Rae, Bethany Rae, Rebecca Rae,.... there's loads of other first names that I think would sound stronger with the name Hall to be honest