All lovely names!
I would choose Ella because it’s pretty, suits all ages, it’s been consistently popular for a while (not faddy) and it’s not as overused as Ellie. I would like to be called Ella!
Ruby and Holly are my second favourites from your list - both are also names that have been popular for a while and suit all ages. I like them both.
Grace - is lovely but it would worry me that the child might not be “graceful” looking!
Maria - is nice but sounds a little more old fashioned to me than the others - maybe due a revival though!