Marianna doesn't sound very upperclass to me. I'm pronouncing it "
Mary +
Anna."
Anna endings always sound like
Pollyanna, kind of silly, sorry. I much prefer
Mariana, "mary-AH-nuh" or
Marianne.\
But to answer the question asked, how about:
Marianna Beatrice Tyndale
Mariana Pilar Velasquez
Marianna Lucy DeVere
Marianna Aurelia Hyde
Mariana Ines de Castro
Good luck. I'd love to know what you ultimately decide on. Thanks!