Trigger would move up, sear would move down. Receiver can have lots of space behind the striker, all the way up to the buttplate, but it can be made shorter to keep the striker spring compressed. Does this look like it would re-cock properly? What would be a good starting spring weight for the striker (20lbs?)?
I would imagine that it's best to weld a rectangular locking block to the bolt and attach the bolt handle via a hole going through the locking block and partway into the bolt...most rigid that way.
The receiver would extend over the chamber area for strength. I am reasoning that and the double thickness compared to the designs using better steel would provide a sufficient safety margin. Any materials engineers here who can add suggestions?