Encounter Help: Can you help me spice this up?

I actually think using bridges would be more fun, as the apes have climb speeds. Have it start off normal, fighting on the rope bridges in the middle. As time goes by, and the apes appear to have disadvantage, they could flip on the underside of the bridges and hold onto the ropes/between the planks. For added tension, they could even start breaking the boards in half, making the pc's have to jump. The apes could gain the advantage, using their hands to hold onto the ropes, and using their feet to grapple the players while they can only climb and hang on for dear life. Save or die can be pretty rough. Maybe have the tree extending over a chasm, with a river underneath. They cold wash up downstream somewhere, either on their own or awaken by the kong creature and a large group of apes.

Don't forget make him half-monk with staff as preferred weapon

Oh! That's awesome! Means the apes can use tools and taunt to the npcs to ramp up the tension. Lol.

Thought I'd share with everyone how the session went!

So the party manages to make their way up one of the uninhabited tree houses without alerting the apes. Two rope bridges lead from this house to the other two which are full of apes. The player with the cloak of the bat flies around the village, while the barbarian uses beast sense to see and hear everything that the scout saw. They formulate an elaborate plan over the course of a real-time hour, involving distractions pulling all the apes to a choke point while the player with the cloak of the bat flies around and rescues the fairies. They plant cordon of arrows and ball-bearings at each junction to slow down the apes that might follow them on the bridge.

Eventually they creep out across the bridge, when one of the cordon of arrows gets triggered by an ape moving around above the forest canopy out of sight. They hear the grunt of pain, and everyone loses their mind. They all just bullrush into one of the rooms and get themselves pincered by all the apes just hanging out in there.

The players in the house fought hard to take down the apes, but each attack did pitiful amounts of damage and it was a drawn out battle. On the way to this encounter, they faced off against a couple black puddings and their weapons were degraded in the process. The player with the cloak of the bat is a freaking badass though, she flies from rooftop to rooftop, staying just out of reach of the apes. She fires off a couple arrows into some hornet's nests and occupies 5-6 apes all by herself. Only one ape fell to the forest floor, but it was a dire ape and miraculously managed to not die after falling 80 feet. But the players saw the damage and seemed to finally grasp the the danger of falling. Because most of the party was indoors, only one of the players got to witness how the apes can utilize the terrain to their advantage.

Then I started playing the sound effects of a giant's footsteps thudding in the distance. Another round goes by, and then I start playing the sound of trees falling over. Finally, one more round, and they hear a terrifying roar and all the apes who are able to begin to run away. The party finally realizes that the dire ape they're fighting isn't the BBEG, and starts to panic. They don't have a quick way down from the trees, due to the fact they were determined to bring their giant goat companion with them. (Long story how they got him up into the trees) As the player with the cloak of the bat flies over to rescues the captured fairies, the rest of the party start tying a rope to the goat, attaching it to the end of a bridge (which is about 40 feet long), and start cutting away at the ropes, and there's a moment when it looks like they're going to have a Temple of Doom moment where they're all going to swing off the building down to the jungle floor. I had always planned on having the fairies fly them out of there, and I was very worried that this would result in a lot of deaths. (5 medium-sized creatures and 1 large-sized creature would likely be a terrifying amount of momentum) I felt bad not letting them have that indiana jones moment, but I would've felt worse if they died.

Anyway, they all fly away as a king-kong sized gorilla throws boulders at them, smashing against trees near them, but they roll different checks to escape, dodging through low hanging vines and tree branches.

In the end all the players were happy! So thank you for all your ideas