Horizontal lines can be created using HTML or markdown coding.

---
Or
<hr>

Aligning images

<div class="pull-left">img  URL here</div>
<div class="pull-right">img  URL here</div>

<center>![](Img URL)</center>

Not possible for different fonts. The font given is one of the most legible anyway. :)

I use a mixture of both markdown and HTML to format my posts. Here's a great markdown reference. https://en.support.wordpress.com/markdown-quick-reference/