Navigation in Storyline

I have attached a .story course that you can download at this link:

www.knowbase.com/content/aama/navigation.zip 

Our client has specific navigation requests. They would like the course to have restricted navigation. This being said, we have made the menu restricted and added triggers to each slide that prevents the learner from clicking the Next button until the slide is complete. On certain "engaging slides" this requires the learner to view all layers before the Next button will become active. 

However, we would also like the user to be able to click the Next button on slides they have already viewed, without having to review the slide again for the Next button to be active. In other words, once a slide is viewed, the triggers set up to block the Next button would be over-ridden and the learner would have "free" navigation on all slides they have viewed thus far. 

I understand that by setting all slides to initial state, this will cause the slide to replay and the triggers in place will prohibit the Next button. However, when one sets it to resume saved state, the learner would be taken to a completed slide, with an active Next button. This would solve the client's request, however, the Replay button does not work when slides are set to resume saved state. We do NOT want the learner to have to click on the seek bar in order to replay the slide. 

Is there a way to have the seek bar function when slides are set to resume saved state OR is there a way to add a trigger that will over-ride the variable that prevents the Next button once a slide is viewed?