So is jungle Ekko still a thing?

Wouldn't recommend going jungle , doesn't have great sustain, or relatively fast clear, just great teamfighting at the end is the only thing he has goin for him. If you get past the early phase with a couple kills you will become a concern.

He's still viable. The highest ranked player I know (Challenger 5s) runs it.

Yes and no. It works it's just not as strong as other picks now. In fact I checked up on pro games stats and builds on Ekko's and they play him evenly between tank/ap jg or just straight up ap mid.

I was able to run Tank Ekko recently and did pretty well and I don't play Ekko very often. He ganks pretty well with his stun zone and dash.

I saw it twice today, utter trash