I have now added all the sounds and the creature animations. I recorded/made all the sounds myself, an example of one would be the rustling sounds which I made by rustling one of my bonsai trees. This sound was used for the Grass Stalker's movements through the grass. The others were various clicking sounds I made etc, all used for creature and environment sounds. Originally I planned to only make some of the sounds myself, and then source others from free use websites, but after checking a few and reading their terms, it did seem a little suspicious, especially as one site which stated that all content must be the members own work, I found a sound on there that I recognised from a game! So rather than risking using copyrighted sounds, I created them myself! I used an app on my phone called Easy Voice Recorder to capture the sounds. I was able to vary them in the sound editor in UDK to get the most out of each sound wave file. I used the free program Audacity to fade out and fade in the two wind sounds I made so that they would loop more seamlessly.
I did make a small mistake while animating one of the creatures however, where I hadn't placed the creature in the starting position before animating. So once I had key-framed it's movements, I wanted to move it to start slightly lower, and of course that changed the position of the entire animation, so luckily I learned from that one mistake and redid the animation again in the correct starting position.
I also put in the kismet event of one of the Tree Rays falling out of a tree, which is something I wanted to have in right from the beginning. The video below shows the sounds, and the other creatures now fully animated. The level is now finished!!