Custom Cart Abandoned Cart Module Development

We have a custom shopping cart written in PHP/MySQL. We have a basic abandoned cart module, that stores the cart info and send an email at a set interval. We'd like to add several features to this: 1. Ability to store notes on the abandoned cart level 2. Log notes with user and timestamp 3. Ability to assign user to cart 4. Add several search filters to filter abandoned carts by 1. order total 2. assigned user 3. contact info (has info/does not have info)