"Those names are long."

Translation: Ta jména jsou dlouhá.

[PhilCostin]

Jsou ta jména dlouhá?

[VladaFu]

That is a question. A correct one, but not a correct translation of the declarative sentence above.

[p8c]

or what about "Ta jsou jména dlouhá."?

[VladaFu]

No, here "ta jména" belong together. They cannot be separated.

If you want "These/those are long names.", you can have "To jsou dlouhá jména.". But here "to" does not belong to "jména" but to the "to jsou/jsou to" pattern.