Manage user profiles with WordPress

As you are going to enter all data by yourself you can make use of Custom Post Types.

Create 3 CPTs for each user type, Trustee, Alumni, Scholar. And with that create custom fields as per your need for each CPT.

Once all data is in, then you need is to create Custom Page templates for each post type where you can list users in your design format.

You can easily find plugins for creating CPT and Custom fields quickly.

Cheers!