Out of Character: I already added the advantage in, though consideration of those who do not already have proficiency and expertise in Stealth could probably make better use of it. Thanks you for the aid, it is appreciated.
Out of Character: Daishain, what is the distance between the two towers?
Velon waits just inside the doorway of the first tower they took, letting his skilled teammates do what they do best. He watches the tower they are taking for signs of trouble, the keep for any watchers on the walls, and towards the right hand tower they have thus far ignored for any trouble in that direction. He will plan to meet the group at the base of the keep wall for the climb once the far tower is secured. He conveys this to Lora and Cratol each via the message spell as they depart, simply saying. "Will meet you at the base of the wall once the tower is taken. Up to Cratol and Lora on how best to secure the grappling hook for the others to climb."
Out of Character: Not quite sure where it is best for Velon to stand during this, so I figured under cover is safest. Good to have some eyes covering the group from a different angle temporarily. He will trust in the others to decide how to set the rope for the climb, whether it be Lora choosing to fly, Cratol tossing the hook up, Cratol climbing the wall, asking Poljen to make the climb, etc.
Cratol takes a look at the barrels, but they're sealed tight. Without the right tools, he'll have to break them open to find out what is within.
It probably doesn't contain alcohol, as those usually carry a maker's mark. It could be water, or foodstuffs such as salt preserved meat, or various oil products. It is tough to say.
Out of Character: There's about a 600' span in between each of the towers you have seen.
Out of Character: . Oh yeah, way too far. I’ll say Velon follows the group but with the same priorities of watching their rear and for any enemies on other walls, towers. He’ll enter the base of the new tower, but go no further unless something happens.