I've verified that the latest version of ALEC (1.0.2) works perfectly fine in standalone and distributed mode when using Horizon 25.
But, when using Horizon 26, it does work in standalone mode, but not in distributed mode.
On karaf.log at Sentinel, I can see an exception when trying to install the sentinel-coordination-zookeeper feature. I'm attaching that log for reference.
I can share my Docker/Vagrant playground for reference if required.