Thanks for the update!
I don't know if Tobiwashio follows Shakespeare's characters but so far we have:
Hikiya Juri = Juliet Capulet
Chiba Ryuuto = Tybalt Capulet (that's how Tybalt pronounced in Japanese but cmiiw)
Tamon Hiromi = Romeo Montague
Banba Rio = Benvolio Montague (coz Benvolio pronounced as Benborio and Banba is most possible surename than Benbo)
The Kijinumas = Gregory and Sampson, servants of Capulet house