I like Estella slightly more because Liliana. However I do think Liliana goes better with Isabel. Isabel & Estella both have such a strong 'el' sound and the 's' sound that they are too similar for my taste.
I've actually gotten used to Liliana or Anna with Isabel since you've mentioned them so often. ;-) Having said that, I think I prefer Estella over Liliana / Lily. It just seems more fresh and is quite pretty.