Once you have compression established then you can proceed to the next logical step.
You said you have already checked the intake for obstructions also don't forget to take into account leaking pressure on the turbo output. I know you'll have to do that later.
You also said that you checked the exhaust for obstruction and also checked the prop and shaft for drag etc and your results were OK with them. As long as nothing was missed or overlooked and providing the compression is good the next thing is to check out the injector pump. I am assuming everything on that engine is mechanical.