Do you think Zoro is fighting Aokiji then?
That depends what the setup will be by the time SHP vs BBP happens ( if it even does ).
I have a hard time imagining Kuzan staying with BBP until the end. He either deflects or whatever.
Let's forget about him for a second.
Luffy vs BB and Zoro vs Shiryu.
Shiryu won't be a challenge for Zoro from a power standpoint. He would literally have to have ( is there a word like that LOL ) Lunarian boy + Flames + Zoan fruit to tank Zoro's attack as he wants and we know this won't be a case.
I say Shiryu will be Zoro's AdvCoO training since it's the only Advanced form Zoro doesn't have yet.
So it will be more so a training dummy for Zoro rather than an opponent.
If Kuzan stays then it complicates things.
I seriously can't imagine SHP winning by then considering Blackbeard can just tap Luffy and make Nika gone.
Overall I think BBP will be finished by someone else.
Luffy can't fight everything and everyone. Oda just won't have time for this.