Yes.  If your earned income in 2020 is less than your earned income in 2019, you have the option to use the 2019 earned income figure to compute EIC. 

You neglected to include which software youre using, buut in ProSeries its on the EIC worksheet.

"If so, do we also include the low 2020 income on the tax return?

I dont understand this sentence.

You prepare the return as usual.