Singular or Plural

Hello, I would like to get opinions of native speakers which sentences are correct among the following and why?

1. In the presidential poll, we have given (singular) an unprecedented 10,000 + plus calls to the public to get their opinions whom they will vote for among the five presidential candidates.

2. In the presidential poll, we have given (plural) unprecedented 10,000 + plus calls to the public to get their opinions whom they will vote for among the five presidential candidates.

3. In the presidential poll, we have given (singular) an estimated 3,000 calls to the public who are still up in the air whom they would vote for among the five presidential candidates.

4. In the presidential poll, we have given (plural) estimated 3,000 calls to the public who are still up in the air whom they would vote for among the five presidential candidates.