Hello :)
I have already developed login, register and forget password functionality in my project with validations. I can complete this task in next 1 to 3 hours. If you want, I can also show that functionality before starting.
1. After Login: UserId and Email will be saved in the session, so we can use where ever we want.
2. After Registration: A email will be sent to the user with a link, once he clicks that link, the user will then able to login to the system.
3. Forget password: There are 2 possibilities:
a. I will send a link in the email to reset password
b. I can send new auto generate password
Whatever you think is best let me know. I have also seen your pdf file which you have attached to your description :)
Thanks and Regards,
Nabeel Abid