Salam Zia Sb,
Wish you have a pleasent and joyful journey.
1) At least 6 hours from Gilgit to Phander lake.
2) Road is good enough for any car.
3) Weather would be moderate, with cold evenings and nights.
4) After Phander, there is no road. Only mud and stones track. Though the journey is joyful till Chitral but not on a car. You need high clearance vehicle with strong suspension. People would claim to have taken Vitz upto Chitral but I don't recommend.
5) Nellum Valley is great. Car can go till Kel.
6) Road from Kerun to Sharda to Kel is still the same, might have worsened. I was on a jeep, so it didn't matter for me.
The rented jeeps are not comfortable at all. But it will sure save your car's suspension. Include Kutton and Ratti Gali in your trip. Arung Kel is also great place but needs a brave heart to ride the desi chair lift and steep hike afterwards.
Enjoy your trip. Stay safe.
Eid Mubarak