I'm guessing that English is not your first language right? Well, from what I understand you are asking, here are my answers:
The Morgo barrels are not Nikasil, but iron like your standard ones are, so the clearance is down to your the company who do the rebore if one is necessary.
That is an interesting mod you've done to your crankcase there. I would say you need to put your return line filter into the return after your bypassed oil and scavenged oil come together as the muck that comes out of your engine will be 99% in the scavenged oil.