Good day Vaibhav_arora,
I think most people are not sure about the visa restrictions but in the wake of recent developments things should be more relaxed.
There are places in Pakistan which even us Pakistanis know of are wonderful but avoid going there due to recent security issues, unfortunately Balochistan is on not recommended list these days, you would either need to take security along from Government or some local tribal leader (choosing either one and this is a tricky one) if you wish to proceed to Balochistan. Hingol National Park is best approachable from Karachi instead of Quetta, Makran Coastal Highway is safe as long as you dont stop at either Hub or Winder and take bypasses of other towns, there will be coastguards on the highway and they check identification it would be in your own interest to contact your embassy in Karachi and make sure if you guys need any kind of permission before entering Balochistan (this could save you a lot headache) we were once turned back from a checkpost halfway to Kund Malir as we were not carrying documents of the vehicle. Please do not proceed to ormara, pasni or gawadar and return back after viewing the wilderness of Buzi Pass in Hingol National Park.
I think you can skip Hana lake as there are plenty to see in KPK including Swat and Kaghan valley which shouldnt be a problem for you provided you are planning your trip in the right season.
Your two main destinations Quetta and Peshawar are an excellent choice for any history lover but unfortunately freely accessible to local tribal people only, and unlike the days of 70s and 80s are no more tourist destinations.
Please note that these are my own views, from a person based in Karachi who have never been to Quetta or Peshawar, people living in other areas might consider Karachi as a no go-area, I hope some local member can guide you better, please also keep in touch with your embassy here.
Can you kindly indicate at what time of year you plan to visit Pakistan, as it would help other members in drawing your travel plans since a lot of places are weather dependent
my best wishes are with you