Hello Steven. Yes the Moodle Teaching Basics program is for newbies with the editing teacher role, rather than your role which looks more like a non-editing teacher role. So doing all the courses is a bit of overkill. If you scroll down the Educator category you will see several courses on Assessment, for example Assess your learners and Assessment:Exploring Gradebook These might help, along with as you say, the grading bit of Moodle Teaching Basics.
The Academy courses are all on 5.1 so they will work for you.
In the Frequently asked questions you have a couple of answers to your question about reusing Academy courses on your site (short answer, yes)