I just did this in January. I made ressies for 5 p.m. Spectro was at 7 p.m. and Wishes at 8 p.m. We left the restaurant at 6:30 ( I know, I know, I didn't have time to stake out a claim) We took the monorail (just one other stop before MK) back to the Magic Kingdom, and by the time we had our bags checked, and went through the turnstiles, the parade was almost ready to begin. We had a window of about 12 minutes. We stood on the porch at near Tony's Townsquare Restaurant. We weren't up front on the street, but we could see just fine. I had someone with me who had never seen it before, so I was glad she got to experience it.Oh, by the way, we ate at 'Ohana.
Given the tightness of times, if I were you, for just that day, I'd either park at the MK/Ticket & Transportation Ctr, take the Monorail to the Poly at 4:30,( or leave the car, take the bus from Port Orleans to MK, then take the monorail from MK to Poly) --check in as early as possible at Kona's. Leave the restaurant no later than 6:30. After spectro/wishes, either take the tram to your car, or hop on the bus back to Port Orleans. It can be done. You just have to be aware of the time and give yourself enough time to get from point A to point B. Always, always, always, allow for the unexpected delay.