Just for speculation on the filler material:
Is the information stated only about him being Oda's design? Nothing else? If so, then I may be hopeful enough to state that it's still possible we'll get ACE FILLER out of this. I mean look at 'im: big mother, obviously lots of character went into his facial hair. Sounds like he could be the result of a bad tipoff of Blackbeard's location.
Just because it's filler doesn't particularly mean it's automatically Luffy and Co.. Ace is large fanservice material, and Arabasta proved that TOEI isn't afraid of extending his story into filler. Also, in lieu of future events, this will be TOEI's last chance to do "Ace chases Blackbeard" episodes, and if I were them, I'd milk it for all it's worth.
Anywhoo, looking forward to new OP and filler regardless.