Timber frames do not have the ability to resist lateral loads by the requirements of modern building codes. There is a performance factor for each type of frame (ordinary vs special steel moment frames, unreinforced CMU or concrete, and specially detailed versions of CMU and concrete, wood sheathed, etc.). The intent is to capture the ability of the frame to plastically deform and absorb energy without failure (essentially the hysteresis losses).
Timber frames were removed from the tables a few years ago. I am not aware of the specific reason, but I do know that nearly all structural engineers, myself included, will not count the performance of the frame in lateral loading. Wood makes for lousy moment joints over the long term.
The classification is mostly important due to the prescriptive requirements of the code (i.e. - number of stories, special reinforcing of CMU and concrete, etc.) and does not replate to the forces specifically. To find the forces on a building, you have to get the USGS accelerations for the probabalistic earthquake, then multiply by the weight and modification factors in the code (for the simple method). One of those factors is in the table mentioned above - without a factor, no analysis is possible per the code (though a value of 1.0 would likely be appropriate, if wildly conservative).
The cantilevered post method is allowable, but you will find that it is grossly inadequate for all but the lightest structures when your post is wood.
If it is feasible, you might consider tension rod bracing which is hidden in the straw bales. The rods (think of the X brace rods in pre-engineered metal buildings) could be connected to the wood columns, though detailing would be key to their performance.
