Progress So Far, Advice Welcomed

[T3chnic4l]

So I started in on tearing my 1975 XS650 w/ 12,378 miles apart completely 7 days ago. Here is where I'm at today. Everything was going very well, my hiccup is I have one very stuck piston. The cylinder walls to the top of the pistons are smooth and not rusted, one piston will move the other is lodged in place. The crankcase all can move smoothly, pistons were open to the air. In the right piston I found dirt, mouse fur probably, and nutshells (Yep, walnut shells). So I need to get it free, I have a mix of Marvel Mystery Oil and PB Blaster sitting on top. Once they are free what do you guys suggest for my next step? Also I know I need to clean and lap my valves and their seats, I've watched the videos and have the right equipment, any last minute tips? Here are the pics of it all, enjoy.
Thanks Guys.

 

[Reid]

Inspect the cylinder walls, possibly try to clean them up with a hone. If that works out clean the pistons up throw some new rings at em and put it back together. Another option would be pick up one of those awesome long rod kits, send the crank and cam to Hugh, have the head ported, have the new sleeves installed in the cyl, pick up some Lectrons.....You know since its already apart.