Your kites are unconventional in some respects, but what is most important performance seems to be good. There is also undeniable benefits to have relatively low cell count, like you explain correctly.
I like how the bridle is designed, it is quite logical and simple. Perhaps total length of it could be a bit shorter, esp. third level of it. ZI 11 and 12 lines can be shorter. You don't have to follow bridled ribs for Z (it is totally free if they are at 100%), I wondered if it was possible to cascade three Z primary lines together and to have only two secondary lines instead of three.
Plan view of the kite is nice and classic elliptical shape. Canopy curve is a bit mild to my contemporary taste, but you have solid arguments for it too.
In general I think designer must be able to give reasons for every part in his kite.
C-line row D-ribs are less than optimal because of their low angle, but hard to say if it is a problem after all. If you had C line row bridled on every rib you could leave them, save some weight and have full line support there. Different line rows can very well be different.
And how about half-cell D-ribs? If you want to keep low cell count but to have smoother upper skin (which is most important) they are worth considering. If you make them from A to C and continue from there with miniribs you can have practically doubled cell count on upper skin. In the early years I made some kites with half-cell D-ribs, they worked fine.
I also like how you present your kites, bridles/lineplan and details. But I'm not sure if bridle/mixer adjustment descriptions are correct (is lower camber or lower AoA really better for upwind? - it may feel like it but feeling is not necessary the truth...) But these are not very essential things and it is good to have a possibility to adjust anyway. BTW there is some problem to scroll down to see line lengths of 15m kite.
That lollipop is cool