pension arrears from central government employee

Monthly pension is taxable, under head salary.

The rebate u/s. 89(1) can be claimed over the arrears.

Refer: get-help-with-salary-arrears

1. Yes..........

2. For arrears form 10E is to be uploaded separately........

Yes, but that you are supposed to claim by filing ITR (in addition to form 10E)

In that case self assessment of the salary receipts including arrears in current year (in the year of receipt)