He will definitely appear in Rocks or Kaido's Flashback
Other than that, don't expect him to appear again
Movie Strong World is neither Canon nor Non-Canon
We can't say it's Canon cuz it didn't happen in Manga & doesn't add up to any Story, it's existence is not necessary
But we also can't call it Non-Canon, cuz we've read Chapter 0 & Strong World is continuation of that
It's basically left for Fans whether to consider it part of Story or not
If they want to see more of Shiki & check what happened to him, then they can read Chapter 0 & then watch Strong World Movie
But if he is irrelevant to them, then they aren't missing anything
Lurking Legend is obviously Rocks D. Xebec
And i will give you a Single Argument to prove it:
When Shanks met WB, Oda said that he was gonna make them talk about Shiki, but then changed his mind cuz it might Confuse Fans
Oda admitted that he believes adding Info when it's not needed is a bad move & might risk take Fans to so much unnecessary thinking
That's why he never mentions things in Arcs that don't fit in them, he wants his Arc Stories to be both Self-Contained & part of the bigger picture, this is why Oda wouldn't bother talking about Rocks Pirates multiple times unless it's a necessary part of Wano Arc.
Rocks is the Lurking Legend & that's why Oda isn't hesitant to keep talking about him
The same Author who refused to mention Shiki in WB/Shanks Meeting to not confuse Fans