You have done a very good job. Congratulations!
Some small remarks:
I wouldn’t use the id attributes as they are not necessary in this context
In the “Exotic dance moves” section you could use a description list instead of an unordered list as this is more semantic: <dl>
You should wrap both addresses completely with <address> tags. This way you could get rid of some <div> and <p> tags and therefore the markup becomes more meaningful (see below)
<address class="sender-column">
<strong>Dr. Eleanor Gaye</strong><br>
Awesome Science faculty<br>
University of Awesome<br>
Bobtown, CA 99999,<br>
USA<br>
<strong>Tel</strong>: 123-456-7890<br>
<strong>Email</strong>: no_reply@example.com
</address>
<p class="sender-column"><time datetime="2016-01-20">20 January 2016</time></p>
<address>
<strong>Miss Eileen Dover</strong><br>
4321 Cliff Top Edge<br>
Dover, CT9 XXX<br>
UK
</address>
If you have any further questions, feel free to ask.