I must admit I was surprised at your post mainly due to having signed 4 cabin crew off as trainers just on the back of being a line training Captain.
I have zero clue about the cabin crew function apart from appreciate a cup of tea occasionally. But my signature was all that was required. Did have one CP who trained 10 of them of them and he had operated single crew for most of his time out the RAF and when he was in he was FJ,
To be fair absolutely nothing went wrong in 3 years , Next company had a proper empire cabin crew setup.... and it was weekly something happened or hand bags got thrown out the pram....