How to show the node delete tab and put a view in it?
By creating a view with path /node/%/delete, you have completely replaced the existing page (the delete confirmation form). According to Drupal logic, this is normal behavior.

What I would do is:

1) Do not use the page display of your view, but add a block display to the view. Add your message as view header. Place that block above the main page content and restrict it to the node/*/delete path.

2) Create custom module, implementing hook_menu_alter with one line of  code (credits):

function MODULENAME_menu_alter(&amp;$items) {
  $items['node/%node/delete']['context'] = MENU_CONTEXT_PAGE | MENU_CONTEXT_INLINE;
}


Of course you need to replace MODULENAME with the actual name of your module.