Keychain issues after Sierra
tldr: No, you don't have an issue going on with keychain. Yes this could be a contribution to the hanging and very slow systems right now.

I have also been experiencing SERIOUS freezes with everything. I also have these same log messages for nearly every currently running application/task being spammed into the console at a ridiculous rate. Running terminal commands takes 10+ seconds in between input and forget a git status with this.

Apple has always had an unreasonable fetching rate for AddressBook, Calendar, and other apps which always cause these log issues since el capitan. 

Currently Safari and WebKit is being added into this mix with it being quite unstable and has been since Sierra's beta throwing these log errors.

&lt;compose failure [shared UUID]&gt;


The log rate is quite substantial and is more than likely the reason or atleast a major part in our very slow systems right now.

Mid 2012 Macbook Pro Retina 2.6GHz Intel quad core here and I've never had it this bad.