Taxpayer has about 30 separate 1099. They include mostly 1099-MISC / 1099-NEC / 1099-K.

1. Is it absolutely necessary to enter all 1099 individually, and then link them to Sch C? Or can the total be entered on Sch C top line alone?

2. Some are issued to the EIN of the LLC that the taxpayer formed, while others are issued to the SSN. I am assuming this requires two separate Sch C?

3. In general, assuming no withholding on the 1099, in what circumstances is it necessary to enter the 1099?

4. What if the taxpayer eventually has an S-Corp, but the 1099 are still issued to the SSN of the sole owner of the S-Corp, even though the funds were deposited into the business bank account of the S-Corp and reported on the S-Corp tax return?