Yes….all themes are accessible with the theme membership.
You may want to stay with the theme you’ve been building up. If you begin again, just start with a fresh install of WordPress, install the theme (the latest version of course). Then get the core foundation of your site in place such as pages, your static front page and another page for the blog, then your main menu. At this point, test the site out in the front-end and see how things look, including the “Hello World” post and see if the comments show for that. Then continue on with the development such as redoing your colours and any other option settings you did before, test the front-end once again. Then move on to adding plugins, and test each one as you install it until you get all of them installed.
As a side note, making websites is not really an easy thing to do, and does take some time. One thing I learned in the past is not to rush a website, as well, always expect the unexpected. Estimating time to do a website, always at least double the time you think it will take. So if you feel it would take 1 week, it will normally become 2 weeks. One of the reasons it takes anywhere from 1 to 2 months to make a theme.