You're right. The Swedish prosecutor and police were present but indeed the questions were posed on their behalf.
> On Monday morning, a Swedish deputy chief prosecutor, Ingrid Isgren, and a police inspector, Cecilia Redell, arrived at the Ecuadorean Embassy, in the Knightsbridge section of West London, as journalists gathered outside.
I don't think this means that Sweden didn't get the chance to ask question though - and if there were any they were prevented from asking, I'm sure they would have stated this in the aftermath.
https://www.nytimes.com/2016/11/15/world/europe/assange-wiki...
>The questions were prepared by prosecutors in Sweden, where an arrest warrant for Mr. Assange was issued in 2010, but were posed by a prosecutor from Ecuador under an agreement the two countries made in August.
>βFor some reason that I am not aware of, I am not on the list of approved persons that Ecuador has established,β Mr. Samuelsson told Radio Sweden.
Assange has already stated that he had sex with both women.