Honestly? Idk. But connecting with the hint we got so far; no interest on marrying any royal suitors, the D moniker, etc. It just seems right.
I also kinda buy the theory of Imu = Imhotep
But then again, this is just my prediction..
When I said grand fleet it basically just means an ally of SHP
Out of all the arguments against Loki joining the crew, I'm gonna say that size is probably the least convincing one.
Here we just got introduced to an owl who can gigantify objects. At the same time, Oda kinda touch on Elbaph being the home of Adam tree. Maybe ship upgrade or new ship?
Also, like you mentioned, we still don't know his df. Who knows he might be able to make himself smaller due to his df.. We'll see.