I had an Easter holiday week in Vienna, and some time afterward.
It seems you can do a lot here! And you can do a lot with kids:
Like: https://star-chemie.at/ amazing, free, and kids are really getting interested in chemistry.
Cobenzl Zoo – a really small, but really cozy zoo, where you can feed and pet farm animals.

Then you can eat some running sushi. You can find a good one in the Yuzu, in Riverside shopping center, 23. district.
Or go to Kino. Mario Super Bros are pretty fun.
Or you can visit Remise – the museum of Transport, for the easter egg hunt. And where you can take a place in Vienna double decker (13A).
Or just take a walk. And one more.