I would normally say Guinevere as I tend to like a consonant starting middle after a vowel ending first - but I prefer Endellion in this case - because of the change in pace between the names, the tailored quality, and how it rounds off the name (so last name would come into play of course as don’t want Endellion to be a full stop). They’re both dreamy and gorgeous names though, and Zara is my niece’s name and I adore it - it’s so swishy and sparkly. She’s nn Zazie.
Others:
Zara Pomeline
Zara Domino
Zara Cecily
Zara Lilouenn
Zara Belphoebe
Zara Iolanthe
Zara Beatrice
Zara Trelawny
Zara Ceridwen
Zara Melisande
Zara Ottoline
Zara Leontine
Zara Leonor(e)
So many other good suggestions above - Vivendel for eg is so lush!
Hope you & Ivo setting in.