I thought "undeserved kindness" was their term for "grace". But it's a great example of the way they change things for the sake of difference.
As for the the video clip, some of it sounds kind of English; it's quite an amusing exercise. I remember a lot of stuff from the 60s and 70s where foreign languages were represented. They never got someone who actually spoke a language to coach the actors in what to say, but would just rattle off something that they thought sounded like the language. As much as I loved Scooby Doo Where Are You, I always cringe at the bit in the episode Mystery Mask Mix-up where Don Messick (Scooby's voice) is supposedly speaking Chinese (Cantonese?) to a bloke in a Chinese laundry in San Francisco, and he's just making a lot of Chinese sounding noises. 🙄
I suppose that all aligns with your original point, that the WT tried to create a religious "sound" that was unique from the the other religions of the time. So the WT buzzwords are just them making a lot of religious sounding noises.