Can we have a picnic there ? Is there space to have a little picnic date ?

Kind of. They have benchs, no tables. Picnics arent allowed for the most part. You can contact them to arrange something.

Generally no, unless you can make do with a few benches.

In November there were some small tables and chairs.

Yes but please puck up after yourself. It's really nice. It would be a shame to see trash al over the place.