Should I change to my new tray that has attachment slots even though I don't have the attachments on yet?

Those are two very different options. Suresmile works with braces and Invisalign is system of clear trays that you wear. Braces will always be a fester more effective way to move teeth depending on what goals your orthodontist still has to complete your treatment.

Systems like  inman aligners have limited control in how and which direction the space gets closed. If you are looking for an aesthetic option you are better of considering Invisalign which delivers much more precise movements.

Your dentist would have the best information on how long they want you to wear your aligners. The refinement trays might have less movement build into each tray so you would not need as much time with them. Seven days still seems very short so just check that this is what they want you to do.

It’s possible for an attachment to wear out or partially break of over time. Depending how far along you are in treatment your doctor might choose to not replace it. If the tray is not sitting in all the way that might also cause the attachment not fully fill in the mold.

If your overbite is that extensive Invisalign might not be the best option. It would only be able to decrease the overbite slightly so it really depends on what your end goal is. They would also have to evaluate if tooth extraction is an option to fully correct the overbite.

You can certainly get your cavities filled while you are in aligners.  Given this situation, I normally fill one or two cavities at a time to make sure aligners still fit properly afterwards rather than filling them all at once.