What i meant by "bone spider inhales before shooting at you" is that on the video you can notice that before shooting shard's at you, you can see that bone spider moves his tail part up and head down preparing to shoot at you
Video - https://youtu.be/WravG9tLqmA
You can make them climb on walls if you make their fire rate in the duration of 2 seconds or like on video and then start that fire animation, in Minecraft Earth, they can climb walls

Will look into this later; animation stuff can take a while