Is it possible to report Scorm quiz results without a (formal SL) quiz?

I'll try to clarify what I meant. 

The Freeform part of the slide would be hidden from the user. They would only see the questions you've already programmed. Triggers would select the appropriate "answer" for the hidden Freeform. Here's one way to do this:

• Put two buttons off the slide. Or use two shapes that each have a Normal and a Selected state. 
• Convert the slide to Freeform.
• In FORM VIEW, indicate which of the offscreen buttons is the "correct" answer. (I suggest naming the buttons "Right" and "Wrong" or something like that. In other words, give them meaningful names.)
• Add a trigger to the Submit button that changes the state of the "Right" button to Selected with whatever conditions are needed to verify that the user answered your question correctly. 
  • Include an "Else" action in the trigger that will change the state of the "Wrong" button to Selected (so that will happen if the "correct" conditions aren't met).
  • Be sure this trigger is before the trigger that submits the interaction/question.

That creates a standard graded question that can be scored by a Results slide and reported to an LMS/LRS. But the user will only see and interact with your custom questions.

Since you only have 5 questions, another option would be to submit the results of one disguised multiple-choice question that is Scored "By choice" (in other words, one that gives partial credit for wrong answers).  For example, let's say each of your 5 questions is worth 20 points. The FORM VIEW of the question slide would look something like this: 

The actual responses would be completely covered by something else, so the user couldn't select any of them. You would add triggers to select the appropriate "answer" based on how many of your custom questions were answered correctly. (This is similar to what is demonstrated in the "Partial Credit" tip I linked to in my previous comment.) 

By the way, this article has info about sending the value of a variable to an LMS: Storyline 360: How to Send the Value of a Variable to an LMS/LRS - Articulate Support