Natural Building and code compliance in lane county, OR

Im buying land in lane county, OR pretty soon, and Im planning on building my own house. I'd prefer to use natural materials, but it seems that building code is pretty strict. I read that if you are building a structure that is a max of 200 sq ft that you dont need a building permit, but it cant be a primary residence. Im wondering if this is old news, now that lane county allows tiny homes? I would prefer to build with cob or strawbale, but as a last resort im thinking log cabin. Another thing i have been wondering, is if it is an issue to have multiple residences on one plot of land? Anyone have experience or advice? Would be much appreciated! Thanks!

According to this page, it looks like Lane County just implements the standard Oregon codes (which are usually a pass-through implementation of the national codes):

https://lanecounty.org/cms/One.aspx?portalId=3585881&pageId=4311173

The Oregon codes can be found online here:

https://www.oregon.gov/bcd/codes-stand/Pages/adopted-codes.aspx

It comes down to doing a lot of reading.  For instance, here's the document for building planning:

http://legacycodes.iccsafe.org/app/book/content/PDF/2014/2014_Oregon/14_Residential/PDFs/Chapter%203%20-%20Building%20Planning.pdf

Near the end of page 11 is the seismic standards description for areas classified D1 and D2 (Lane County is D1, which you can find previously in that document).  So, adhere to those standards or the ones they refer to.  And then move on from there.  It's a lot of work, but doable, and you end up learning a lot.  For instance, with a little digging, I found the code for straw bale structures:

http://legacycodes.iccsafe.org/app/book/content/PDF/2014/2014_Oregon/14_Residential/PDFs/Appendix%20R%20-%20Straw-Bale%20Structures.pdf

Hope this helps.

Cheers.

JD