I'm afraid you are wrong on several particulars of Allomancy. First, there are sixteen ordinary metals that have Allomantic properties.Second, each God metal has either sixteen or thirty-two alloys (either 1 or 2 for each metal, Brandon has hinted at two).
The rule of sixteen is confirmed by Brandon himself.
Also, as I pointed out above, I have reason to believe there are five kinds of BioChromatic entity, not four.
While you are probably correct in there being four ways to access the Dor, (there is a fourth confirmed magic system on Sel, but we don't know which Shard fuels it), it is about as certain as it's possible to be that Devotion is behind AonDor and Dominion behind Dakhor, and that undoes your balance.
Finally, this half of your post seems to argue for my theory while the first half argues against it.