Change behaviour of magento to accept mobile number instead of email id everywhere

Here I am describing my full requirement. 1) Customer should be identified by his mobile number, instead of email id. It means customer’s login id / account id is mobile number instead of email. Once user is registered and verified his mobile number, he/she cannot modify it from anywhere (e.g. from my account) 2) Mobile number field is required and mandatory field for customer registration. It should be unique as well. 3) Email field will be optional for registration. 4) There are many email templates in magento for sending email to customer for variety of events (e.g. order placed, order cancelled). We need to have provision to send SMS for all events when magento sends emails. 5) If customer has entered valid email id in email field and if it is verified then email also should be sent along with SMS. So we should not disable emails, but add extra code to send SMS. 6) On new registration screen, Customer’s mobile number has be verified by sending OTP on his mobile (I have SMS gateway API to send SMS, I will provide it). Customer’s account has be activated upon OTP verification. 7) User can enter email id on new registration screen or Later modify/enters from my account screen. On both cases email id verification email has be sent on specified email id, this email should not contain password of user. 8) When customer click on link provided in verification email, system should ask his/her login password before performing email id verification. If password is correct then email id will be marked as verified and activated for sending all sort of notification to it. 9) Welcome SMS on successful verification of mobile number by OTP 10) SMS for Order placed Successfully (In case of online payment, Only after payment process receives payment successfully). Note: - All above requirements should be there on front end and admin panel both - I could specify the cases which we could think of, but it is your responsibility to cover all other cases based on dependencies analysi