The door looks normal to Salty, or was at one time, before it rotted away. He pulls on it and it falls aside with a wet thump into several pieces, leaving the doorway open. He sees the room beyond is small and mostly taken up by the stream, which runs under the wall across from him.
You all hear some shrieks and growls, and several monkey-like creatures with long claws on both hands and feet converge on Salty. There may be more creatures in the room by the sounds - these three are crawling on the walls inside of the opening and about to swarm the Halfling.
Surpise? d6=1,1 - you are surprised by the ferocity of the attack, while the monkey-creatures are surprised by the door falling away.
DEX of monkeys is 3d6=10. Order of actions is Cedric, Salty, Berthod, Suspos, Monkeys (simultaneous with Suspos), Heimer, Schmidt.
Here are the positions I think you would have approaching the door, let me know if they have to change and what your actions are. If you stay in the doorway, only two can attack in front with Heimer and his spear behind.
Salty falls back with Berthold, while Cedric moves forward to present a line against the creatures. Heimer has his spear ready from the second rank.
As you move into position, three other monkeys emerge screeching from the room, now six total.
Of the three of you in the front line, only Cedric is able to wound one of the creatures.
Four of the monkeys swarm onto Cedric, and three manage to sink their claws into the gaps in his armor, holding fast but not yet drawing blood. Two monkeys swipe at Berthold, but are not able to latch on.
You hear Suspos intoning the words to a spell, and all six monkeys fall asleep (the three on Cedric are still latched onto his armor). At the same time, Salty and Heimer collapse to the cavern floor, also asleep.
All is quiet but for the snoring.
Status:
One monkey is wounded but all the monkeys are asleep. Salty and Heimer are also asleep.
Order of actions is Cedric, Salty, Berthold, Suspos, Monkeys (simultaneous with Suspos), Heimer, Schmidt.
Round 1:
Cedric vs. monkey: d20+2=21 HIT for d8+1=3 dmg (wounding one)
Berthold vs. monkey: d20+2=7 MISS
Salty vs. monkey: d20=11 MISS
Monkeys attack in groups (d3=1 Cedric, d3=2 Berthold).
Four monkeys swarm onto Cedric and the remaining two attack Berthold.
Monkeys vs. Cedric: d20+1 x 4=2,18,18,19 for 3 HITs the monkeys latch on to Cedric but do no damage this round.
Monkeys vs. Berthold: d20+1 x 2=9,8 MISS
Suspos (simultaneous with the monkeys) casts a sleep spell. It affects (which of the 1HD vs. 2HD creature groups, d6=1 so 1HD) 4d4=11 1 HD creatures, which is all the monkeys as well as Salty and Heimer.