Having a few issues with my site

Hi there friendly WP people. I’m new to this and pretty naive, I know very little about coding, css, etc so please be patient.

I downloaded the Mystique theme from digital nature and I am very impressed with it, for a complete novice it made a cms site very easy to design. But there are just a few little tweaks I would like to make to my site and am stuck for clues as to how to do it.

My site is highlandtruffles.com.au

The issues I’m having or things I would like to change is as follows

? The Blog, as you can gather from the text below it in the sidebar, its not creating the right custom permalink and leaving a / out
? I’d like to lower the header. I’m working on re-sizing the image so I keep the width but reduce the height, but i would also like to lower it towards the navigation bar. I have disabled a Mystique function that pops up a twitter and rss feed on the right hand side above the nav bar so I guess I would need to remove the code somewhere.
? Changing the favicon. I have created one and then followed the steps here https://www.computer-realm.net/how-to-change-your-wordpress-favicon/ but cant seem to get it to work. Any ideas?
? How do I create a subject line when people click on my email link on the contacts page?

Many thanks in advance for any help offered