Nothing on the head of the piston looks like it was affected. We never talked about your cylinder to bore clearance, which is something that your manual isnt going to be much help with, since you are not running a cast piston and you are not using a plated aluminum cylinder anymore.
that being said, when we all used iron liners the seizure you show was not all that uncommon. Lots of us stuck them early and simply cleaned them up and ran it again. (So I know about acid cleaning.) Still kind of smacks of a cold seizure. I would consider a breakin with a 16 or 20-1 mix if you don't find an airleak by my method or similar one.
Clarify for me, is this the first one you seized on the 134 kit?