California has very strict architect and engineering regulations. Where local law or ordinance requires drawings and calculations to be prepared by a licensed professional, they must be prepared by or under the direct supervision of a licensed architect or engineer. Thus, your architect will have to start from ground zero, even if you hand her/him Internet plans.

Chances are the Internet plans may not conform to all applicable California codes and regulations (Energy conservation, for example), and certainly do not take your property into consideration. So an Internet plan will have to be modified to conform to these.

Finally, the plan may not meet all of your family's objectives, and if so, modifications may be needed.

So if I understand correctly, you will have to pay the Internet plan factory $4K, and then have all of the other modifications made which are necessary to satisfy your family and to obtain a building permit.

I don't know the size and quality of your desired house, but it seems to me you're already at $10K (or more) using your Internet plan. Would it be cheaper and better to simply use an experienced architect? Have you talked to any to get a sense of their scope of service and fees?

Good luck on your project.

Also don't underestimate the good ol' boy network. We used an architect and GC who grew up and live in our CA town. Amazing what knowing the inspector will do for you! Be prepared for high permit fees too.