What are "Squad Perks?"

Solution 1:

Squad perks are perks that span across all of the members in a squad.

1. Squad SPRINT(Rank 23) - Makes you and your squad run faster. (+10%)

   Squad AMMO(Rank 26) - Lets you and your squad hold more ammo clips. (2x's as much)

   Squad FLAK (Rank 29) - Gives you and your squad more armor from explosive damage. (-10%)

   Squad EXPL (Rank 31) - Gives you and your squad more rocket ammo, C4, and mines. (2x's as much)

   Squad SUPR ( Rank 33) - Makes you and your squads bullets have more of a suppressive effect. (+50%)

   Squad COVR (Rank 35) - Makes you an your squad more immune to suppressive fire. (-33%)

   Squad FRAG (Rank 37) - Gives you and your squad more grenades. (1)

2. No they do not stack with individual perks, plan your squad accordingly.

3. No you do not have to be a squad leader for the perks to work for the squad. The leader does not have to have a squad perk if he doesn't want to, it doesn't matter.

4. The squad perks are very effective, they are essentially the individual perks but span across your whole squad. Once you have them you can no longer access the regular version of the perk.

Courtesy of @CruelCow this link gives you some insight as to percentages of benefits and how they scale.