As with all weapons questions, make the weapon fit the fighting style and terrain.
Since your critters are aboreal, that means they are going to be in trees. Unless it's a redwood forest, there is not going to be room for big swinging weapons. Anything too large or long is not going to be great because you need room to swing the weapon. How do you get lethality without a big swing of something heavy? Make it small and sharp, or even poisonous! Think mostly about thrusting weapons.
For weapons, I would think anything longer than a Roman Gladius is going to get tied up in surrounding foliage. The Gladius has a great tip for stabbing. Long Daggers and spikes, that sort of thing. Cutting edges are fine, but should be a secondary consideration. The answer with Dragon Claws is another great idea. You could probably work the Kama or a similar weapon in as well. It would have to be a short handled version though.
Your weapons should also allow for gripping while still having a weapon in hand. As your critters are hexapodal, this should give you some leeway. Wolverine like claws, spiked brass knuckles, WWI trench knife designs all come to mind.
For Ranged weaponry, as mentioned elsewhere, blowguns and shortbows. Close trees means longshots are more or less impossible, so longbows are out. Crossbows are also less likely, as they are too slow. Jungle fighting is going to be a fast affair. The time it takes to cock and load a crossbow is just too long.
Armor and shields are likely not going to be a big thing. Your creatures need to move and that is hampered by excess mass. The shield takes at least one hand to hold, and that hand may be better used to grab a branch. Armor has weight, and it will make climbing and moving slower. I have a feeling in combat, slower will mean more likely to die.
This brings us to poisons. Fast acting poisons are going to be favored. The blowgun has served some indigenous peoples for thousands of years. You can adjust to account for poison dart frogs either being in your world or not.
That covers warfare while out and about. You towns may be a little different. If you have stable and secure platforms to stand on, you will see longer weapons appear. Spears, Hooks and the like. These will also be more for thrusting than swinging. Slightly longer bows and maybe even crossbows will be useful for defending a fortified position.
The Ultimate weapon would be fire. That is only for the most suicidal, but fire would be a threat for everyone. Another big weapon, in the place of medieval sapper, would be the guys who slash all the bark around the trunk of a tree. This would kill the tree over time, weakening the whole structure.