1. Thereís fewer/the least/less space in the new flat than in the old one.
Correct. "Less" for uncountable quantities.
2. The square is more or less the same as / like/than it was fifty years age.
The square is more or less the same as it was fifty years ago.
3. This hotel is best/the second best/the better in the city.
4. I canít see any difference Ėto me theyíre a little bit/exactly/slightly the same.
5. People have been trying to cross the border/edge/front/side into India.
6. Itís a twelve-hour flight/fly/travel/plane from New York.
7. The scene/scenery/sight/view from the top of the hill is absolutely fantastic!
8. The old market is one place thatís really worth see/seeing/to see/to be seen.