Regarding the menu items, the Bushwick theme automatically includes a "Home" link that sits on the same side as the sidebar column. The custom menu, however, appears in the white space as you mentioned. This is the intended look of the theme as shown in the demo here:
However, if you create a custom menu, the theme will remove the Home link on the left-hand side. Instead, your custom menu will be reflected in the white space, which I believe is what you're looking for. Can you try creating a custom menu following the instructions here?
If you would still like to have a "Home" link that directs users to your home page, you can add one as a custom link:
I was also wondering if and how can I change the font and size for the text of the titles and the text.
In order to do that, you'll need to purchase the Custom Design upgrade as explained here:
Please let me know if you need anything else!