I’ve had the same idea. I couldn’t reason out if it could work or not, so thanks for trying it out. Reconsidering it now, with your low line tension comment, you could make the top bridle be wider than the bottom bridle. Taking that to the extreme would be the top bridle going to the wingtips, and having no bottom bridle. That way the top bridle would have a bigger moment arm than the bottom bridle and so would have a bigger influence. You could do moment arm * line tension comparisons to see what could maybe work. You can do the same for all the kites down the train.
Within your design constraints, I like my cam-actuated cyclic banking idea better.
I like having a lifter kite, if for no other reason than to prevent the kites from falling to the ground if you stop rotation.