[salayc]

You need smog to register which requires cats. You can get an independent VIN verification which will get you through the visual inspection required for registration (in addition to the smog visual.)
I don't think you will have a problem with insurance. I have insurance through Haggerty and a couple of others. At most they ask for pictures of the car, but for an agreed value policy, I don't think they care. There are some well known workarounds for all of this too.