If the price of the underlying moves higher and if your Long Put position is OTM, this position will not require any additional margins. For the Long Option position, the additional margin is required only if the position is ITM.
For Long Futures and Short Call position, the margin requirement will increase on the day of expiry to 40% of the contract value or SPAN + Exposure margin (whichever is higher). You will continue to get any margin benefit, you were getting. You can check out this post for more details: Relaxation in Physical Delivery Policy - Margins collected
Yes. Contract Value = CMP * Lot Size for Futures and Premium * Strike Price * Lot Size for Options.