Three Things

Gravity Engine:

Considering that this is all fictional, make the exoskeleton an armor-like suit, in its core, place a gravity engine/plasma reactor, which will power the suit. This engine could be connected up to every part of the suit. For the higher-ranking officials, throw ina gravity gun too, which could function as a portal gun too - manipulating gravity to create controlled wormholes.

Wingsuit:

This wingsuit should be designed in tandem with the gravity manipulator/engine, this combination will allow the user to glide more efficiently. The wingsuit should be made out of a material with high tensile strength and surface area, this will make it function more efficiently, allowing for precise tactical insertions. It needs to be collapsible, preferably able to fold away into the suit. Here's an idea:

Either way, it must be reusable and able to fold back into the suit.

HUD and AI

A HUD and AI are imperative for this system to work, the HUD will allow the user to view their surroundings and their altitude, target, velocity, and so on. The AI which will be wired to the user's brain will allow the gravity manipulator and wingsuit to work in perfect harmony with pinpoint precision.

How it will work

First, the HUD will display the user's target and the most efficient path to get there. The user will jump off the building, using the gravity engine and wingsuit to quietly glide his way there. Here, if the gravity engine fails, the plasma reactor will go into overdrive, sending plasma down specially designed vents at velocities that will be calculated by the AI, to slow their fall enough that the armor will be able to withstand the fall if stealth is necessitated, then a grappling hook will allow to user to hang on to a point and slowly lower themselves. Next, the user will begin circling above the target, slowly losing altitude as the AI scans the area for hostiles and analyses the landing area. This will allow it to optimize the suit's stealth field generator for that area. Then, the user will take out their weapon and stay upright - toes down as the gravity engine decreases power, allowing the user to fall until they reach 5 feet above the ground, at which point, the gravity generator will kick in, slowing their speed to millimeters per second; when they touch down (in a 3-point landing, the gravity engine will kick into stealth mode, allowing the user to move without making any noise. The insertion is complete. In a pinch the user can overclock the gravity engine, creating an impulse that will allow them to glide to safety. The gravity engine will also allow the user to climb walls like Spider-man.