Your computer might be too slow to update them frequently. Do you know your computer's CPU?
You're not very clear on what is too slow and what takes 5-10 seconds. Could you please reiterate?
I'm pretty sure they have different sound effects. They do sounds similar, however. Correct me if I'm wrong though, I haven't tested this on your platform.
You can use dyes to change the text color on signs. In my opinion, this is much easier than Java edition.
Yeah, sometimes mobs are hard to find in Bedrock. I can usually find them with ease in small bodies of water and the Plains biome.
Might be your internet. Did you check your connection strength? Try moving closer to your router.
Try restarting your device. If that doesn't work, try uninstalling and reinstalling the game.