Blog, changing colour of slider font

@Potzas: I see that you have static content in the home and blog in Blog page. It’s going good.

I would also like to make the overlay header on the slider a blue font, not black.
— Just change the color code as per your need and add it in your “Appearance => Theme Options => Custom CSS” box.

#main-slider .entry-title a, #main-slider .entry-title span {
    color: #222;
}

I would also like to change the sub-heading on the home page, I want it non-italic and I would like to change the font colour there as well.
— Add the following CSS in “Appearance => Theme Options => Custom CSS” box.

#homepage-message span {
    font-style: normal;
    color: #858585
}

@Potzas: I don’t understand your question.

You have blog at this page http://reefadmin.com/blog/ this list all your blog posts. But you have hide your blog title here. So, you can recover that by adding in the following CSS in “Appearance => Theme Options => Custom CSS” box.
.page.page-blog .entry-title { display: block; }

Then in homepage you have static content. But if you want to add additional page. Then first go to “Appearance => Theme Options => Homepage Settings => Homepage / Frontpage Settings. Then check “Enable Latest Posts or Page” then go to “Settings => Reading”. Then in “Front page displays” setting check “A static page (select below)” and select “Front page” with the page you want to add in homepage. But don’t change anything in “Posts page”

Add the following css to get the featured slider headings
#main-slider .entry-title { display: block; }

Is there a way of moving the featured content to the bottom of the text on the home page, rather than at the top?
— For this you need to customize the theme by building child theme. You need to get developer to do this for you.

@Potzas: Yes add the following css and change the color code as per your need.
#main-slider .entry-title a { color: #000; }