Is it likely the ELD mandate will be delayed?

It isn't delayed. This is the newest thing I could find.
House rejects ELD delay provision

There's a 2 year period after December, this year, to be grandfathered in if you meet various requirements, I haven't read the whole thing. I think you already have to have elogs or an AOBRD .
Implementation Timeline

 

I hope your safety lady isn't counting on it. You'll all be stopped for a while until the ELD supply comes back.

 

I don’t see it happening, too many big money supporters in favor of the mandate. Every attempt has failed and they’re running out of time considering how long it takes anything to happen. I just wish they’d start focusing on the asinine hours of service regulations instead