Agree with Vance.
Anything less than 10 in the brood boxes is asking for trouble:
You get wonky comb and lots of drone brood. You get bridge comb, and an inspection mess. You get comb that has folds and doubled areas.
The logic that comb number had to be consistent comes from the belief that the frames need to be lined up exactly to avoid blocking the bees moving up.
I don't observe that as a problem. The bees seem to ladder up the air space between the boxes no matter what the frame count. The usually build some bridge comb to connect the supers off the bottom bars of the box above. Possibly the shift in spacing acts like a partial queen excluder-- divides the brood nest from the honey by the partial barrier.
I run 10 for brood, start with 10 for honey supers, and after the first extraction, I run 9 (or 8). I never start with undrawn frames in loose spacing. Two reasons: the frames are too heavy with honey to extract the weak, new comb-- they blow out, and the frames are likely to get wavy comb from the spacing.
Pulling 1 or 2 drawn frames from each box at the first extraction has the advantage of letting me build up new supers that are pre-checkerboarded. This is a huge advantage, as it allows me to super up very simply with checkerboarded pattern that encourage the bees to move up.
In tight spacing the outside of the 1st and 10th comb is usually initially skipped. I rotate the comb into another position, or just flip it to face inward.
In my "eight frame" boxes I run 9 for brood, as the standard "eight frame" box dimension has an excess free space. (I don't know how or who set the dimension, but it has more slop than the 10 frame standard). I run 8 for honey in the narrow boxes, but after experimenting with eight-frame, I am back to building mostly 10 frame boxes for my own use. I sell the 8 frame hives to eager novices, however.