It’s definitely going to depend on how the data is collected and what you’re trying to achieve. You could certainly render each worksheet individually and then combine them into a final master project, but you could also merge all of the data into one large sheet to create a ‘flat’ JSON file. That may allow you to combine the scenes without having to render or replicate the project multiple times. Instead, you could theoretically create sub-comps and then use the Time Sculpting features of Templater to resize the individual sections as necessary.
After looking at the data in your JSON example, you might consider a setup where you create a series of blank videos or comps of variable durations and then load them with the ‘duration’ data point. You could then use Time Sculpting to trim the image and text to that blank placeholder’s duration as needed. Again, a lot of this will depend on your setup, so if you have any specific questions, please just let us know.
As for your question about what version you need, it sounds like your setup will be best served by either the Pro or Bot version of Templater. If your final goal is full automation, Bot will probably be the way to go, but if you’re mainly looking to replicate and iterate large numbers of videos, Pro should be fine.