I co-taught a course in data stewardship last year targeted at graduate students in agronomy, most of which had never coded before. We started with Rmarkdown because it is generally a very good first coding experience. If a student makes a mistake, they will not get what they want, but they will probably not get a frustrating error.
We also started early with GitHub because all assignments and projects needed to be submitted via GitHub. We used SourceTree because almost none of our students even knew what the command line is (and I certainly don't use it). If I did it again, I would teach Git through RStudio. I think RStudio has improved on this and I feel like SourceTree gets worse with each update.
Getting into R, we were really torn on what order we should teach things in. Visualization first, Tidyverse first has a lot of good arguments, but were nervous to do this for people who were still wondering, "What even is R?". R4DS was mostly available, but not quite done at this time. I think that, selfishly, we wanted students to have enough base R background to truly appreciate what the Tidyverse was doing for them, although we never really put them through the ringer. We also thought they would probably encounter and work with some base R, so better to do it with us than in the wild. It seemed like the order worked well while we were doing it. The course was not required for any of the students, so we had a mostly willing audience.
Overall, however, I'm not sure I can say the course was a success. We had 15 students, many of whom I still work with on various projects. The few who already used R continue to do so in their own fashion. Those who had not used it, do not use it now. One person uses Rmarkdown. Zero of 15 people continued to use GitHub after the course (yes, I stalked their profiles).
You can find our course materials here: http://agron590-isu.github.io/syllabus.html. The spring following our course, there was a similarly-minded course taught in the Stats department and I think it may have done a better job of a lot of things - https://stat585-at-isu.github.io/syllabus.html. I feel it was targeted at a very different audience, I'm not sure which yours is more similar to.
Hope this is helpful. I'm late to this thread, but considering whether I should teach Data Stewardship again in the spring and what changes I would make. I may teach straight out of R4DS.