I have been to many JW funerals over the years, though with my advancing age suspect there will not be many more left for me to attend. As some have said here the talk depends on the speaker and to an extent the congregation elders. Certainly where I live it has to be an elder if the service is held in the KH.
Some years ago I went to the funeral of a very old sister, in her 90's, who had been a JW since the 1940's. Surprisingly the funeral was not held at the KH but at the crematorium. There were two speakers, one of whom was not an elder or even an MS. The other speaker I had never met before. The talk was mostly about the sister, her experiences as a JW and her very interesting life away from the organisation.
At the end of the talk there was a prayer and then her favourite piece of music, Verdi's Nabucco. No Kingdom songs, wonderful!