Setting up Ubuntu pref.

Hey!

Haven't used Ubuntu ,or Linux in general for a few years. (So I have no clue what I am talking about.) Just installed Ubuntu 16.04 LTS on a spare laptop I have. Went well, but I have a few questions.

First thing I did was to update, I searched for "Software Updater" in dash and ran it, everything went straight forward.

However after when I did:
sudo apt-get update
sudo apt-get upgrade

It seemed that "Software Updater" had not updated everything.

Question 1: What terminal commands are equivilant to the "Software Updater"?
Question 2: How do I navigate to "Software Updater" without going via searching?
Question 3: What is the prefered method of updating Ubuntu? (Software Updater vs sudo apt-get upgrate/upgrade vs sudo apt-get upgrate/dist-upgrade)

System updated, I went exploring:

I noticed that "System Settings - Secruity & Privacy - Search" is toggled to "OFF", which should prevent online search results. (Amazon, etc) Great! However I downloaded and installed "Unity Tweak Tool" and navigated to "Unity Tweak Tool - Search" and noticed "Show "More Suggestions"" ticked, which displays "If enabled, show applications available for download in the Dash" if mouse is hovered over.

Question 4: Isn't the "OFF" supposed to prevent all online searches? Not just "Search online sources", which is unticked in "Unity Tweak Tool".

Let me know if I am missing something, I believe this should be unticked due to "OFF" being toggled.

(I tried searching for "VLC" and "VideoLAN" but got no results, so it might not be effective, even if the box is ticked. I am assuming it searches "Ubuntu Software" for "applications available for download". Regardless I will disable it, if I need some application I won't search for it in dash, but in "Ubuntu Software".)

I had the extras option ticked when I installed, for .mp3, etc. Can't recall exactly what it was named, but since the "Software Updater" seemed to differ from terminal, I decided to try:

sudo apt-get install ubuntu-restricted-extras

It went on for a minute installing.

Question 5: Was the full package not installed upon installing Ubuntu? Only parts of it?

Thanks!