I think all the options have been suggested. If you want an app, go with Tapatalk. If you want a simplified theme, go with Artodia but I find that too simplied for the ipad. It's better for the phones. iPad works better with the full theme. My site
serves the mobile version of Artodia with an option at the bottom to switch to the full theme. If none of that works, pay someone to write a custom app. Themes are not apps. Themes cannot do push notifications and other iOS functions. Themes are nothing more than window dressing.