First, I would like to say that I like what you did with the theme, the site looks really nice. Well done.
To answer your question, I checked both the title font family and size of the page and post, they are both Opens Sans and 30px large. The difference is that the post title is a link which has the yellow color you chose. That is why it’s yellow.
Traditionally pages don’t display featured images unless you place them in the body of the content.
You could create a post and link to it in the menu, which will look and behave like a page.
Let me know if that answers your question or not?
Let me know if I can provide further assistance.