Hidden Launchd Process
Forgive my absence and untimely response. Okay, let's take this to the next level.   

Let's attempt to locate either coconutBattery or Sparkle, a dependent, apparently.  Do you find a 'coconutBattery.app' in /Applications, or any similar app?

sudo find /Applications -iname "*coconut*" -print    
sudo find /Applications -iname "*sparkle*" -print


Is there a relevant package receipt in the package utility?

sudo pkgutil --pkgs | grep -i coconut
sudo pkgutil --pkgs | grep -i sparkle


A brute method to find plists, preference files:

sudo grep -l -i "coconut" -r /System/Library/
sudo grep -l -i "sparkle" -r /System/Library/
sudo grep -l -i "coconut" -r /Library/
sudo grep -l -i "sparkle" -r /Library/

sudo grep -l -i "sparkle" -r /private/var/
sudo grep -l -i "sparkle" -r /private/etc/
sudo grep -l -i "coconut" -r /private/var/
sudo grep -l -i "coconut" -r /private/etc/


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Interesting situation.    

First, let us determine in what user-context the service is running: login user, or root.  I suspect that the service might be running in the login user context, which would explain why you will not find it by running 'launchctl list' as root ( via sudo ). A quick check:

launchctl list | grep -i "com.coco"


Avoid prepending 'sudo' to the launchctl command.  

Also, the process id is reported in the syslog messages -- found within the block brackets [ ].  


  com.coconut-flavour.coconutBattery-Helper[23430]


The PID is 23430, in that example. I suggest using a ps like this:

ps -wwwAxo pid,ppid,state,%mem,%cpu,command | grep -i coco


Or grep the PID you discover from the syslog like this:

ps -wwwAxo pid,ppid,state,%mem,%cpu,command | grep 23430


If my hunch is correct, and it is under your login user's context that the service runs, then locate the offending plist in something like:

/Users/[your login user's short name]/Library/LaunchAgents


A quick-and-dirty method:

grep -r -i "coco" ~/Library/LaunchAgents/


This should identify the offending sneak.  If not, please let me know and we will then take the hunt to the next level.