W/salam brother.
Although i am not at all a guru shuru type, but let me try to reply ur queries 1 by 1.
1- is it ok to travel with just my wife alone on such a long journey ( i would be 31 next year)
Absolutely no problem.
2- what are the best times to leave lahore and what are the places i need to stop till hunza or should i do it one stretch ?
Leave Lahore before morning (say 2-3 am) and try to reach near Naran before evening. Night stay can be at Kaghan, Naran or Battakuni as per ur liking.
3- how would be the weather in july in Hunza valley, would it be same as naran or a bit hot ?
It is generally hot in summer sunshines
4- i will be with my wife so planning to stay at good family oriented hotels, can 100k is enough for the whole tour including fuel ?
July would be peak season, but this much budget seems pretty ok.
5- what are the best places in Hunza to visit and can i cover astore, rama deosai in the window of one week ?
U can go till Khunjerab with Attabad Lake, Gulmit, Sust etc on its way. Duikar, Baltit Fort, Altit Fort in Hunza are nice places to see. U can also go to Naltar for a night. U can also spend a night at Rama while return Journey
6- I am planning to stay at serene Inn hunza or Darbar hotel, which one you guys prefer and when would be the best time to make reservations as i have heard its a peak season and very hard to get rooms in these hotels
No personal experience of these, but must be quite costly in peak season. This year i stayed at Hotel Hill Top. this is a mid range but sufficiently gud hotel. Good thing is that they dont allow bachelors or male only groups to stay in the hotel. So families feel very comfortable.
7- Someone was suggesting to me that i should go in august/ September as july would be a rainy season so there are alraming chances of land sliding and floods in those areas and if you get stuck with family than things can take a really nasty turn in no time so is july the right time to visit hunza ?
If u can change the timeframe, then IMO best time to visit is either June or September. But in June, Babusar is often closed. September would be off season too, so u would have better hotel rooms in same price range.
8- Do i need to carry my nikaah nama with me as someone told me that good hotels in hunza don t rent out rooms to couples ( just making sure no sudden troubles 
)
I am not sure about that, but better to carry at least a photocopy of that.
U can also have some guidance on my this year trip of Hunza via Naran.
4 Day Tour de Naran, Babusar, Hunza, Attabad Lake on Nissan AD (9-12 Aug 2015)
