Hello,

to show 'other information' when clicking on a contact, just use any of the links that show a contact in modals. The global configuration options for the Contact component or the Trombinoscope Contact component will determine the content of the modal. Just make it so it shows the minimum data, down to just the contact information.

If you use Trombinoscope for other forms, I would suggest you link the contacts to the 'show contact (no form) in modal (Joomla Contact)'. Like that, you use the core Contact component just for that purpose.

If any element remains and you don't want, you will need to use CSS to hide them.

As far as the modal view is concerned, the extension uses a layout you can override.
You can find the layout under your template settings, in the tab 'create overrides'. Go to the layouts section, com_trombinoscopeextended -> content. Once the override created, you will find the code under your template's html/layouts directory.
Modals use the component.php template file to show content.