I can only relate my personal experience, but that has been my observation. The other two K brands seem to use less figured wood in their base models, but they (appropriately) charge less.
You will always find individual instruments that will not conform to this generality, but on average I think this is the case.
Sorry, I highly doubt this. Kanilea offers three "grades" of curls in their Koa wood: the least figured is called "Select", followed by "Deluxe" and "Premium". These three options are even used on their most basic K1 models, but will cost more accordingly. Again, you're paying for the beauty of curly wood, not necessarily for a better sound. My own observation is that on the entry level models from both Kamaka and KoAloha, you'll get an equivalent of "Select" Koa wood, while they use the more figured pieces for their more expensive models and customs, such as Jake's Kamaka or the Red and Black labels from Koaloha.