Need to POST API call After Confirmation wait for Processing and Then Confirm by Emai

Zen Cart 1.3.8a
Patch: 1::
Database Patch Level: 1.3.8
v1.3.8 pHP Version 5.2.8
System Linux

Multiple things need to process the order. Let me know if you can help on any of these.
I need to:
Checkout

1. Get Locations where the order can be placed based off of pulling from Vendor site and zip code selection using GET to pull variable list ( customer will select on the Checkout page)
2. Store info in custom fields in db

Confirmation

1. After Paypal Pro Confirmation that the order has been paid, send the order to a vendor via an api call with the full order details via my "POST" API call
2. Ping for the order to be approved by the vendor
3. "GET" the order information via API calls and store the order info in the database
4. Once order has been completed. Get the order info and have available for client to view results on line.

Any ideas?

All of your desires will require a good amount of custom coding and Database work