In names there are much similarities. Sydney could already be in Spanish because it's spelled and pernounced the same. Remember names could have diffrent spelling but the same pernounciation and meaning.
The same name can be used in Spanish.
hola mi nombre es Courtney
the name Sydney is actually the same in spanish spelled but can also be pronounced Sidnehy (Si-dneh) because in spanish e's are pronounced eh.
Sydney's name is just Sydney. It's not spelled differently..
Sydney Fairbrother's birth name is Sydney Tapping.
Sydney Sidner's birth name is Kathryn Sydney Sidner.
Robin Sydney's birth name is Robin Sydney Heymsfield.
Sydney Spies's birth name is Sydney Elizabeth Spies.
Sydney Streeter's birth name is Sydney Stanley Streeter.
Sydney Wong's birth name is Sydney Devonne Wong.
Sydney Wolofsky's birth name is Sydney Lynn Wolofsky.
Sydney Wiles's birth name is Sydney George Wiles.