It appears to be possible to create Print Replica locally by feeding the KPF output of Kindle Create to the
KFX Output plugin CLI.
These can be side loaded to Scribe and the iPad app (where you can add highlights and notes). I have not checked yet to see if Share works (Scribe) or Export (iPad). Most likely not, but there's always screen capture.
Update: There is something different about KFX generated from
KFX Output than that generated from Send To Kindle. The conversion from KPF to KFX is being handled by Kindle Previewer, so maybe that is missing something.
Side load KFX to the iPad app of the former does not let you select text etc, but side loading the Send To Kindle KFX (sent to Scribe) will (however there is no Pages preview as there is for Print Replica store content).
On the Scribe itself, there's very little difference that I have noticed so far. So it might be good enough to experiment with.
And Share/Export goes through the motions of things, but nothing gets exported (as one might expect).
From Kindle iOS app it does send email, but the .html file is empty. It looks like it is once again sending PDFs from Send To Kindle service, there was some sync of reading position with Scribe a couple of weeks ago, but that seems to be gone.