HI,
As per section 10(10 A iii), any payment in commutation of pension received from a fund is not taxable.Hence if you choose for full maturity complete payout option in December 2019, this transaction may not be subjected to tax.
On your second query, the credit of the TDS can be claimed only by the person whose TDS has been deducted. It belongs to deductee not the deductor. The taxes paid will be reflected on the PAN of that person. Hence, he can claim the same in his return.
Thanks
Damini