Apart from the spellings being horrendous (IMO) I think they'd be fine.
I know the majority seems to think "Its like they have the same name!" But they don't. The fact is that
Isabelle is a name separate from
Elisabeth. They may have had a common ancestor but they are different names now. If you were to ask this question on a site about names but perhaps not with name nerds you'd find a very different response.
Its when parents name children
Lee and
Leigh,
Mary and
Marie,
Anne and
Anna,
Jon and
John that they're annoying. Those names, though different, not only sound alike but are also spelled similar. That's when you should be getting people yelling at you.
Just my humble opinions.