Regarding Revised Return

You can only revise (belated) return for FY 2016.17, till march 2019.

Revision of belated return was amended from 01.04.2017., previously belated return could not be revised.

Law up to AY 2017-18, Revised return can be filed up to one year from the end of the relevant AY or before completion of assessment, whichever is earlier.

So in your 1st case for A. Y. 2017-18 the last date of revise the return is 31st March 2019, and,
for second case i.e.for the assessment year 2016-17 the last date of the revised the return was 31st March 2018.

So you are only eligible to revised the return for the assessment year 2017-18 i.e. previous year 16-17.

The above last date are subject to completion of assessment by Income Tax Department.
Thank you.