wow what a gorgeous hamster!
you're definitely right about the wheel, its great that you already know about proper wheel sizing
Its actually extremely easy to tell what gender a syrian hamster is. from the first picture, Chubbs looks like a boy, but it was a little bit too blurry to know for certain. males will have 2 very obvious balls in the back...
He also looks pretty full grown from those pictures.
Hope the 2 of you really bond and have a great time together!
dont tell my dwarves but syrians are by far my favorite hamster breed