Enel can simply stay away.
and Lightning can't pass through Ice like Magma would.
Regular lightning ? No. Enel's lightning ? Yes.
Even his casual El Thors can vaporize tons of rock.
Enel wouldn't be able to last 10 days against someone who has superior Speed and Combat Skills than Luffy.
Enel has the tools to beat Aokiji without getting into close combat. He has the traveling speed and range advantage, not to mention Aokiji isn't rubber ( he is ice, so along with the heat property of Enel's lightning the high voltage should have some effect as well )
so he won't be able to shrug off Enel's attacks like Luffy did.
Considering that Kuzan was a former VA, I say there is high probability that he had Kenbunshoku as well and possibly Rokushiki.
Enel's CoO is one of the best in the manga, Island range. Aokiji has no feats to compete in that department. Rokushiki is great and all but it won't do any good if Enel doesn't come close.
To put it simply, Enel can't touch Kuzan but Kuzan can touch Enel.
Actually, given their skill sets it's the other way around. Aokiji would absolutely wreck Enel in a close range fight, but Enel can cover miles in an instant in his lightning form ( shot across Upper yard in an instant )
and he can rain down El Thors from that distance as well.
Since Logia DFs can seemingly produce infinite amounts of their elements this will boil down to a stamina fight. Aokiji has the feats behind him with his fight with Akainu, but Enel is a different animal all together.
If he keeps his distance and launch pin point attacks I believe he can win.
@ the giant pictures.
Maybe. There is a race of giant giants, that has already been confirmed ( Oars, Oars Jr. and San Juan )
. As for how the giant skull fits into all of this, I think it belonged to a giant parent trying to rescue a child in PH.