Upgrade Kirby 2 to 3, controllers

The CMS Questions
1

I followed the instructions to update a project from Kirby 2.5.6 tho the latest Kirby 3 version.
Accessing the page I’m getting the following error:
Error Call to a member function children() on null

This is the controller home.php

<?php
  return function($site, $pages, $page) {
  $collection = $site->pages()->find('home', 'events', 'contact');
  $events = $site->pages()->find('events')->children()->visible()->flip();
  return compact('collection', 'events');
};

Trying to acces the panel, I’m getting the following error:
Error Cannot access protected property Kirby\Cms\App::$roots
…/panel/index.php

// the default index directory
if(!isset($kirby->roots->index)) {
  **$kirby->roots->index = $index;**
}
2

use listed instead of visible, although that doesn’t seem to be the error. Does events exist? IN any case, I would recommend:

  $events = ($p = $site->pages()->find('events')) ? $p->children()->listed()->flip() : new Pages();

Have you removed the old Panel folder?

3

Now I’m only getting one page onto the frontpage, while all the pages should be listed.
Might this be related to the new string above, or do I have to search elsewhere in the code?
Kirby 2.5 https://letterspace.amsterdam
Kirby 3.5 letterspace.amsterdam