I did a version of your proposed hike last Sept/October with two of my teenager daughters (15F & 16F), we did EBC, Cho La pass and Goyko. I think your hike looks amazing, but knowing what I know now I think it is a little ambitious.
I hired a guide and two porters which worked really well. I had done a lot of research before and new which company I wanted to use. I didn't pay any money until I had met the guide in person in Kathmandu to ensure I was happy with him. The key to our success was flexibility in the schedule, we stopped when the girls needed some time out to chill. As mentioned by another poster, it is a physically and mentally demanding hike, there were lots of tears and "I can't do this" type phrases, but now 8 months post hike they cannot wait to go back.
We had acclimatisation days in Namche, Dingboche, we also took Diamox from Namche onwards. Given the time of year you're going is the tail end of the wet season, there is a good chance the planes will be delayed out of Kathmandu. We were meant to arrive on the first flight but infact didn't get to Lukla till midday so Phakding was just far enough to walk to. If we had to go as far as Jorsdale we would of been walking in the dark.
Make sure you take some good broadspectrum antibiotics for chest aliments.
Just a side note, my girls still cannot look at anything made with potato