There's no reason for home button to go missing on 7s if it does have bezels. Remember the haptic-home button (or whatever that is called) is also relatively new introduced only in 7. Assuming camera on that is at par with what you call x-edition, 7s would be my preferred phone. Even with a sub-par camera it still might be depending on the additional cost of x-edition. But I will be a little sad about that.
Considering the new iOS 11 videos demonstrate an iPhone 7 functioning without a home button & countless prototypes appearing with rear facing Touch ID.
I think there could be a slight chance that Apple is going all out on eliminating the front home button experience on the entire line-up this year.
My prediction; (come back here after the event & see!)
iPhone 7s - renamed to iPhone, without home button and rear-facing Touch ID
iPhone 7s Plus - renamed to iPhone Plus, without home button and rear-facing Touch ID
iPhone X Edition - OLED, “bezel-less” design with Face ID only.
And all the above mentioned iPhones will also make magnetic charging the norm, with ceramic backs.