Ok, came up with a plan and a stunt. Vote by name as I may need to make alterations, but I'll let everyone know when they happen.
@Alexander89 - let me know if this works.
[X] After committing so many troops Clovis' base must have few guards remaining. This is the perfect opportunity to reach him.
-[X] Strategy: Order the terrorists to disengage and retreat, giving them a route if there's one available. If they can stow the Knightmares somewhere safe for later use, great, but if not they should abandon them. No matter what they need to get out of Shinjuku, and let them know you'll try to contact them later if you can. They should lay low until then. Meanwhile, you'll head towards Clovis's base. Send one of your minions to recall those already sent so they can give you as accurate a picture of what's going on as possible. While you're waiting ask Seyrun to give you a rundown of the abilities at your disposal. Once your minions have returned get their report. If there doesn't seem to be anyone who can detect them or any other nasty surprises in store begin your infiltration. If they did find something, or they don't return at all, reassess the situation before committing to going in.
--[X] Infiltration Strategy: If an insufficient number of your minions have the Essence to materialize to get you out of a bind or kill interlopers if needed, make sure to let them feed on some Britannian soldiers before you go in. Otherwise go ahead. Using manipulation, you'll get a private meeting with Clovis. You have two pieces of bait to report - the first is that you have information on what the terrorists stole (knowing it is more than just poison gas) and the second is that you have information about traitors in the ranks that allowed the terrorists to get the upper hand and only the Prince can be trusted with the information.
-[X] Stunt: "You there!" you say in the most authoritative tone you can muster, grabbing the attention of the posted guards. You quickly flash your ID card and put it away before they can inspect it closely. "I am with Internal Affairs, and I must speak privately with His Highness immediately. I have vital information about what the terrorists have stolen, as well as regarding possible traitors in our ranks." The guards look at eachother, their uncertainty clear. "But, sir, I..." "No buts! I will not have it! Go now and be back in the next seven minutes or I swear you won't like the consequences!" The guards' terror is evident on their faces, and two of them rush to get approval after a quick "Yes, My Lord!" Not long after, they return. "His Highness will see you in his private chambers, my lord. Right this way." You move to follow, your demonic minions in tow and no one the wiser.