I do it slightly different, after the step through we do a downward elbow right above the elbow on the end of the Tricep and then a cross body shuto to the back of the neck followed by a grab of their left shoulder. The grab is crucial if you are doing the spinning hook kick after the stomp. As you stomp bring your right hand (holding shoulder) to your left hip. this forces uke down and keeps them upright at the same time. I like your variations and starting points of the tech. Something I def. could play around with in the school.
I like what you're saying about the shoulder hold to keep them up, but if you do a little bit of a slower motion when stepping into your spinning hook kick you'll find it's second nature for a lot of people to start standing up immediately after you do the stomp to the back of their leg. Although some may go into a roll or something to get away from the situation, it is kind of hard to gauge what a real person would do on the response of an uke.
Another thing I've noticed about the combinations, especially the first 26, they're for the most part fairly simple to accomplish during a sparring situation, in my opinion a lot simpler than many of the techniques that I've learned. So I'm wondering if this may necessitate a review of which techniques are really worth keeping. My father was telling me the other day that when he trained with Professor Nick Cerio he said he wasn't a huge fan of anything having a lot of strikes in it, that you'd be lucky if you were fast to get off two or three. I guess that's why he was really big into shotokan, and I think you can see that a lot in Nick Cerio's Kenpo... just some thoughts I was having.