reroofing a 1910 home with 2x4 rafter 32" on center

Hi I have a 1910 home with 2 or 3 layers of comp shingles over one layer of redwood or cedar shingles, over 1x4 skip sheathing. The rafter are 2x4 full dimensional and 32" on center. I want to tear off down to the rafters and probably install new 2x4 (full 4"--will probably rip 2x10s or fur). I also want more insulation. What I am thinking is to fill in the rafter bas so the framing will be 16" OC and sheath with plywood or zip roof sheathing. What I would like to do then is where I am needing help. I'd like to install rigid over the sheathing and then a standing seam roof without having to have two layers of ply/OSB (this is earthquake country so lighter weight is better). I have read and been told that this is done but I personally have not seen it done. Is this feasible? And if I put the rigid above the sheathing, I am thinking I no longer will need soffit and ridge venting and hopefully will be able to then fill the rafter bays with rockwool with no gap for venting. Any ideas or help is greatly appreciated

Thanks

Rob