TDS on Immovable property Sec. 194IA

A flat has been allotted to Wife (First Applicant) & Husband ( Second Applicant) by State Govt Housing Board. The total price of the Flat is payable in 10 instalments over 2 years & the last installment is due on handing over of the flat. The flat is under construction & not handed over; hence the last installment is not due now. The Husband Second Applicant has paid all the 9 installments & will be making payment of final installment also. The Wife Second Applicant has not made any payment for the flat. The following may be clarified:-

1. Whether 1% TDS u/s 194IA can be deducted & paid by Husband ( 2 nd Applicant) only by filing a single form 26QB since he has only paid all the 9 installments due so far & will be paying the Final installment also.
2.Whether 1% TDS can deducted & paid at the time of paying final installment for total price of the flat 0r TDS is to be deducted for each Installment paid over 2 years by filing seperate Form 26 QB
3. If TDS is to be deducted for each installment paid in the past two years, what is the rate of interest & other charges applicable.
4. How the Rental income from the flat is to be reported in IT Return. Whether the entire 100% rental income can be included by Husband in his IT return as he has only made payment of 100% of Price of the flat. Or both Husband & wife
has to declare 50% of Rental income in their respective IT Return even though Wife (1 Applicant) has not made any payment towards the price of the flat.