You cant replace the flex cable for the digitizer its not possible to that and as far as the home button it seems like you got a bad part if you hadnt ripped the cable i would say send it back to where you baught it from but idk if they will accept now but cant hurt asking. But your going to need to get a whole new assembly either way and hopefully this time the home button is in better order Update: im sorry now that i actually think about it screen doesnt have home button attached my bad i would make sure that the rubber surrounding the home button stil has stick to it to be able to hold it against the screen and also check the metal peice that the button will be pressing and make sure that it is at an angle that also will help the home button stay up

The digitizer(glass) and the lcd and "glued" together on the Iphone for meanings of a better term. you can rove one from the other but they will break in the process and there is no real way to make them stay together if you did get the pieces separately so yes you will have to replace them both. But be warned there are plenty of fakes out there be sure to get yours from a reputable business and make sure the lcd and digitizer come as 1 piece not 2

I'm afraid not your best bet would be to buy another screen. The flex cables on a digitizer once broken are not easily replaced if at all and best done by a machine because you have to connect everything perfectly back onto the digitizer so you can get those reading that are needed to make it work. You would be just replacing the flex part that your used to seeing the cable its self goes all around the screen.