Vastu has an important role in our life and dwelling place. There can be several different lifestyle interior designs for a dining hall but every Dining hall has to be built according to Vastu rules. If you go against the norms of Vastu Shastra, you will not be able to experience happiness in your family.
no, you can not build a kitchen and dining hall in different floor. Both should be on the same floor.
For remedies read this article: Important 15 Facts For Dining Hall As Per Vastu Shastra | VASTU DEKHO