You have a few options.
Personally, I have a local development setup. So I have WordPress installed on my Mac and I can build everything custom locally. Then when it is completed, I upload the new theme to the live website, install the plugins I may require, update any settings I may need and activate the new theme. Then browse around and check for any issues.
Another option is to create a child theme for TwentySixteen, then I believe you can build the theme while it is disabled but you can preview it under Appearance and click on Customize, where you can customize your theme and see the live preview as well. I have never used Thrive Architect so I am unsure how easy this would be to do.
Another possible option would be to install a plugin like Theme Switcha (I am not involved with this plugin nor have I used it before, there may be better options.) which will allow you to switch between themes and view them on the live site but only you would see them. So your surfers would see the normal site you have now, but you would see the new version you are building.
Again, I build things from scratch on my Mac and I find each theme upgrade or move is unique based on the current setup and what needs to be done, that would require looking deeper.
I hope this was somewhat helpful, if you have a specific question please ask.