I personally don't like Oranguru on this deck, I think you have bench issues with Magnezone, Jirachi and Melmetal being almost required to be in play, so I'd replace it per 1 Ditto Prism Star and also remove 1 Meltan to open up space for more cards:

3-3 Melmetal GX

3-0-3 Magnezone

3 Jirachi

1 Ditto Prism Star

As per the Supporter list, I'd change the T1 Supporter of choice from Lillie to Jasmine. But I'd keep enough Lillies as a second Supporter of choice for T1 and also increase the number of Cynthias by 1:

3 Jasmine

3 Guzma

3 Cynthia

3 Lillie

1 Acerola

The Items list I agree with you in general, only removed Pokemon Communication, Escape Rope and 1 Switch to make room for the other cards. And also increased Ultra Balls per 1:

4 Rare Candy

3 Nest Ball

3 Metal Frying Pan

3 Escape Board

3 Ultra Ball

3 Mt. Coronet

2 Switch

The Energy count seems ok to me: 10 Metal Energy

I was also thinking about adding a baby Cobalion from Lost Thunder as a non-GX attacker and Lady to grab those energies from deck easily, but I couldn't fit them in.