Help Setting Up Payments table functions?

right now in my payments table, I've set it up to where a customer can make several payments on an invoice. But, what I'm looking to do is:

1)want to set it up where the payment due dates are scheduled automatically to specific periods.

2) a notification email would be sent out to the customer if payment has not been received 1 week before due date. Also, an email to be sent out if the payment is past due.

Next things I wanted to do are:
1) set it up where if multiple payments are being made, then an Amount Remaining total that knows when to stop when total bill is reached.

2) a magic button on each payment that not only checks the box but also fills in the payments amount

3) is it possible to automate where if a customer wants to make 3 payments, can it be setup where 3 payments sums, with due dates, are created, and only have to be marked when paid?

If it's easier to explain via email, or a virtual meeting to see what my app looks like, let me know. I am open to doing that. or giving permission to someone to set this up. 

thanks!