Smg, lightweight and flak jacket, toughness and dexterity
I prestige without using my unlock on ghost the first time around and now I am experimenting with it. Idk if it really helps me that much or not
I switch ghost with one of the two perk 1s I listed sometimes. It's still a great perk, I just don't find it as effective now that it only applies to uav's, as opposed to previous games. When I'm sprinting around the map capping flags I know the opponent will know when I am there regardless and I'm going to need protection from their grenades.
Honestly, perk choice is 100% preference. I recommend having classes that differentiate from one another. Having 10 classes all with hardline/ghost/scavenger/dexterity wont do anything for you.
Make a class or two with flak jacket, one or two with lightweight, etc. and switch up your class depending on the type of enemies you face. I generally start off with hardline/ghost, scavenger, dexterity. If I see shock charges, grenades, C4 spam or anything else, I will switch to my flak jacket and tac mask class.