I have KLAX and also installed was Couatl.
That's normal, since KLAX won't work without it.
I do not know why I have it running and I keep getting "on-line" updates for it when I start my FSX flights?
You are not getting online updates every time you start FSX, you are getting online updates *notification* ONLY if we release one and ONLY if you don't apply it OR don't select the option to ignore it.
The option to ignore it will make that notification stops, until the next update is released.
Do I need to keep this Couatl on my PC?
Obviously yes because, as I've said, neither KLAX nor any other FSDT product will run without it, if there wasn't a need for it, we wouldn't installed it in the first place so, you can assume that, if we installed it, is required.
If you problem are the online notifications, as I've already explained, it's easy enough to ignore them so it won't notify it anymore, until the *next* update is released.