This sounds like the way to go -- intimidate, then try to charm. Just gotta wait for confirmation that the other guard is dead. I'll use my turn to Help and provide Inspiration to whoever can best use it.

Who does have the best Intimidation? Like I said, I'm +3.

I'd guess you've the best charisma. I'm proficient for +2 and the last to act

I'd guess Bowlder is proficient for +3 and 13 Charisma. Yordis sheet has him at -1.

Yordis has a mighty 8 for charisma so I'm almost certainly the worst person to make that roll, the plan is good except for that though, let's make sure the other guy is down and we can try it if it doesn't work we can try something else

If I use my next turn to dodge I can probably get away with him missing me anyway, I have ac18 so I'd risk it, then one of you guys can start intimidating the he'll out of him.

Then when I get the chance I'll give the Inspiration to Bowlder, since I can't Inspire myself.

Vicious Mockery will probably have him at disadvantage to attack already. If that succeeds maybe try to taunt him to ensure he attacks a high AC target. He'd be a fool not to be intimidated in that moment.

Or just roll the intimidation with -1

Oh, you're right, I guess he will get a turn before Bowlder could try to Intimidate him into putting his weapon down. I guess I'll try Vicious Mockery.

I bet you'll need to finish off the other guard anyway, let's see what our DM says 

Tilly moves to the door and sets to ready for any other guards that come while the intimidation games goes down. Peeks out into the hall to see what she can see. 

perception 18

Anyone foolish enough to follow on will catch a short sword in the throat. 

Attack with shortsword  19

Damage 6 Piercing

Sneak Attack Damage 4 

(or if Guard 2 is still alive and kicking when Tilly's turn comes around let him have it.)

The second guard is finally dead and the third is to afraid to act on his turn anyway. Make some rolls now people. In terms of the passages, history to see if you remember some thing useful.

History 14

The tunnels around here are anything but simple and there too many potential paths to keep track of, but you have a vague idea of how to get up top.

History 7

I thought history checks were for things like "What was that War?" or "Who was that person?". That's why I threw a perception check earlier. I'm good ether way though. 

History: 19

OOG: On a related note, does anyone else feel like the skills associated with Wisdom are really more attributed to the concept of intelligence (i.e. in the moment assessment? Insight, perception) where as the skills associated with Intelligence are more attributed to wisdom (i.e. knowledge gained through study and info accumulation? Religion, Arcana, history). Maybe this is just me.

OOG: Yeah, D&D has always named those backwards -- Wisdom represents something like intuition, while Intelligence is book learnin'.

History: 15

I think the idea is in the application of it, history is like a test to see if you studied that thing, insight is using your combined life experience and being able to apply it to a situation and I think that is correct. I disagree with nature and investigation for example, they seem wrong.

History: 6

Go ahead with the plan, he's intimidated

Droogan looks over the fallen guards for anything useful or valuable. Then strips off the smaller one's uniform and tosses it to Tily. "You may not blend in well but you'll do better than me."

If they've got shackles or anything Droogan will take them, if not he'll borrow their boot laces

I guess they had to draw a line somewhere for the mechanics. Though naming them something like "Intuition" and "education" might have made them easier to parse without the handbook. Or in the application as Phadeout mentioned.

Valentinus picks himself up off the ground. He starts to smooth out his hair, but then realizes he's still in disguise and no one can see it.

He points his sword at the guard. "Put your weapon on the ground, and kick it over to the lady."