Return of deceased person filed by legal heir

Facts of the case are as under:

1.

The assessee expired last year on 20 September. Most of the assets were divided as specified in the will. As per the I T Act requirements, one of the executors got their name registered as legal heir on the IT website last month. The executor has already filed his return for Asst. Year 2015-2016

The act states that the legal heir will have to file return for the deceased using the legal heir option

Query:

The legal heir will file the IT return for which period

1. From 1st April to the date of death (20th September)
2. From 21st September to 31st March
3. A single return for the whole accounting year April 14 to March 15

2.

The assessee had invested his funds in Company / Bank FDs. Interest earned upto 30 September was credited / paid by these entities post 30 September. The form 26AS does not give a month wise or date wise breakup in few cases

Query:

How do we claim the interest and TDS in the above cases? Should it be on mercantile or cash

1. If on mercantile, how do I account for the interest and TDS upto 20th September and claim the same
2. How can I claim the interest and TDS for the remaining period
3. the interests is shown as receivable and accounted  companies and

3.

The legal heir has registered himself on the IT website

Query:

1. Can the legal heir file 2 online returns for the same year but for different periods
2. Can the legal heir file one online return and one manual return for the same assessment year
3. Can the legal heir file 2 manual returns though he has already registered as a legal heir on the I T website

Thank you all in advance for the replies

Best Regards,

CA CSJ