Hi Lee,
The big picture is that you are trying to make the quizzes work as a formative assessment/mastery learning activity - which is a good thing.
Unfortunately, when you retake a moodle quiz with the setting EACH ATTEMPT BUILDS ON LAST, it only pre-fills in the choices from the last quiz attempt, but will not tell them which of them were wrong. They could open the last attempt in one window, and then take the new attempt in another window, but that's just the way moodle handle's quiz attempts.
https://docs.moodle.org/34/en/Question_behaviours
There's a couple of ways you could handle this:
One way (the way I do it now)
Immediate Feedback
Close date set so they can't just keep taking the quizzes forever
Unlimited Attempts
Each Attempt Builds on Last - Off - Students hate this, but I want to force them to study
Shuffle Questions - On
Delay between attempts - 1 hour
Review Options - Turn off everything for Right Answer except for After the quiz is closed
Students take the quiz, each question has a check answer button. If they get question wrong, they can't change their answer until they re-attempt the quiz, but they do see the feedback. I kinda punish the students when they retake the quiz by making them wait an hour. I also shuffle the questions which forces them to search the old quiz for the question. Some of the quizzes have calculated questions - which is really the best type of question for this, but as you might know, creating a calculated question takes some work.
Another way: (which is more what you want)
Interactive with Multiple Tries (if you hate penalizing the student, then use Adaptive Mode (no penalties))
Close date set
Attempts - 1 - then students don't have to go back an look at previous attempts due to tablet use.
Each Attempt Builds on Last - doesn't matter because only one attempt
Allow redo within an Attempt - Yes - so even if they bomb the question, they can still keep trying just to see if they can get the right answer even though they will get no credit.
Shuffle Questions - On
Review Options - I think you have to uncheck Right Answer for During The Attempt - but i'm not sure. You just don't want to tell them the right answer for the first time they get it wrong, because then they will always get the next try correct. *shrug*, but maybe this has to be checked. Try it out and let me know.
The big issue with this is that you now have to edit each question and determine the penalty and the number of tries under Multiple Tries setting. Watch that video below. By default, moodle quiz questions remove 1/3 of the points for each wrong attempt. So after 3 wrong answers, they get a zero. There's a nifty feature that will allow you to remove the wrong choice they made after they try the question. If you hate penalizing students, you could just do adaptive mode without penalties instead of interactive.
This is probably closer to what you want.
Summary: I think Interactive mode is prone for abuse because students will just click each option till they get it correct. If you don't penalize them somehow, then what is the motivation to actually think about the question? Just something to think about.
Remember that once you have your quiz settings correct, go into SITE ADMINISTRATION->PLUGINS->ACTIVITY MODULES->QUIZ and change all of those settings so that when you create a new quiz, you won't have to remember to change everything again.
