Ok, these problems affect Moodle when denying access to view user profiles and view hidden details (creating a FERPA compliant setup).

The following areas still linked to profiles when in FERPA complaint mode:
participants > full profile in more detailed mode
participants > all images linked to profiles
gradebooks grader report > all names linked to full profiles
tabs > profile tab existed

clicking on any of these generates an annoying error.

Here are the fixes I came up with:

user/tabs.php

around line 92
$context = get_context_instance(CONTEXT_SYSTEM);
if ($user->id == $USER->id or has_capability('moodle/user:viewdetails', $context, NULL))

{ $toprow[] = new tabobject('profile', $CFG->wwwroot.'/user/view.php?id='.$user->id.'&course='.$course->id, get_string('profile')); }

instead of
$toprow[] = new tabobject('profile', $CFG->wwwroot.'/user/view.php?id='.$user->id.'&course='.$course->id, get_string('profile'));

lib/weblib.php

around line 4309
$context = get_context_instance(CONTEXT_SYSTEM);
if ($link && ($user->id == $USER->id or has_capability('moodle/user:viewdetails', $context, NULL))) {

instead of
if ($link)

around line 4486
if ($user->id == $USER->id or has_capability('moodle/user:viewdetails', $context, NULL))

{ $output .= '<a href="'. $CFG->wwwroot .'/user/view.php?id='. $user->id .'&course='. $course->id .'">'. $string->fullprofile .'...</a>'; }

instead of
$output .= '<a href="'. $CFG->wwwroot .'/user/view.php?id='. $user->id .'&course='. $course->id .'">'. $string->fullprofile .'...</a>';

grade/report/grader/lib.php

around line 685
$context = get_context_instance(CONTEXT_SYSTEM);
if ($user->id == $USER->id or has_capability('moodle/user:viewdetails', $context, NULL))

{ $link = '<a href="'.$CFG->wwwroot.'/user/view.php?id='.$user->id.'&course='.$this->course->id.'">'.fullname($user).'</a>'; }

else

{ $link = fullname($user); }

$studentshtml .= '<tr class="r'.$this->rowcount++ . $row_classes[$this->rowcount % 2] . '">'
.'<th class="header c'.$columncount++.' user" scope="row" onclick="set_row(this.parentNode.rowIndex);">'.$user_pic
.$link.'</th>';

instead of
$studentshtml .= '<tr class="r'.$this->rowcount++ . $row_classes[$this->rowcount % 2] . '">'
.'<th class="header c'.$columncount++.' user" scope="row" onclick="set_row(this.parentNode.rowIndex);">'.$user_pic
.<a href="'.$CFG->wwwroot.'/user/view.php?id='.$user->id.'&course='
.$this->course->id.'">'.fullname($user).'</a></th>';

These changes do not affect anyone not running in FERPA mode and make FERPA mode work SOOOOO much better.