Hi, Mike and Stephie.

1. First we will comment about pulling data from Custom Fields/posts in our dataTables.

As the custom posts/fields, are a part of the WordPress database;

pulling this data can only be done through MySQL query-based tables.

Please note: Using this plugin feature requires at least a basic knowledge of SQL. It is assumed that you can create the table in some MySQL data manager (e.g., PHPMyAdmin, MySQL Workbench), and prepare a SQL query that will return the data you need. 

A good way to achieve this can be experimenting using our WPDB SQL Query Constructor tool.

- Please note: this tool is not an ultimate query generator. It simply constructs a suggestion of a query. We are constantly working to improve it, but SQL is such a complicated and flexible language that full automation for constructing queries is next to impossible. 

Consequently, the more complicated the query, the higher is the probability that it will not return exactly what you need. So, you will often need to play around with the resulting query.

Please be advised that writing custom SQL Queries or debugging Queries does not fall under what our support covers.

You can check out this official page of WP codex,  for help with writing custom Queries.

2. We need to edit certain fields  - like client notes :

- Here you can see how to make Editable tables in our plugin.

Please note these limitations on editing tables with wpDataTables.

• Only one MySQL table can be edited at a time. Queries from multiple tables with joins cannot be used as an editable feature, since SQL UPDATE and INSERT statements are generated automatically, and there currently is no way to update multiple tables.
• Only MySQL tables or tables created with “Create a table manually” and “Create a table by importing data from data source” options of “Create a Table” page can be edited.
• Server-side processing MUST be turned on for front-end editing – Note: It will turn on automatically if you forget to enable it.
• MySQL Views cannot be edited properly – only one of the underlying tables can be edited if you pass the proper ID.

3.

• We would ideally like to shift the form to below the grid rather than popup :

I am sorry, but I did not understand what you mean by the grid;

do you have any working example of anything similar to that, or if you can at least elaborate more, what kind of grid would that be and what is the expected behaviour from our tables in this use-case?

4. We need to understand how to make some columns appear on the table but other columns on the grid 

- As in the previous point, I am not sure which "grid" you are referring to.

If you could elaborate on that, please.

Thank you.