Family share

so 2 questions...

will family share work with iOS 7? my 5s is on 8 but I'm keeping this off my wifes phone and sons iPad mini for now. just wondering if it can be done now or do i have to wait till everything is on 8.

been searching for an answer on iTunes match but yet to come across one. anyone know if my wife will be able to access my iTunes match under this family sharing?

basically with some of the bugginess, I'm afraid to turn this on, like to hear from someone who has done it

ok so heres a question. since iPhone 4 isn't supported and theres still some legacy equip out there (some parents don't want their kids to have the latest and greatest as they lose/break etc) those will not be compatible with family share? so it truly is tied to hardware and not the account itself?

for example, i log my wife into my iPad air (also upgraded to 8) and family share her account. when i log her out and she continues to use her iPhone5 on 7.1.1 what will happen?

has anyone come across this?