It's so royal that the obvious boy names would be
Edward,
George and
William.
I like
Victoria.
Charlotte - remove the C- and the -te and see what you're left with. I just couldn't use it, not ever. I'd even prefer
Charlene!
Alexandra is nice but a bit impractical for daily use; shortened to
Alexa, I'd be happy, but
Sandra is a real turn-off.
If you want a regal trio and can drop
Charlotte,
Caroline has a good 18th-century pedigree; or
Catherine if you go back to
Henry VIII and the Stuarts.