They didn't have as much control over Archie's christening because they hadn't "found freedom" yet.

They wanted Archie to be christened on July 4, when the Queen was in Scotland for Holyrood Week, and Charles and Camilla were in Wales. The Queen slapped them down and made them change the date to July 6 so that Charles and Camilla could attend, but she snubbed them and went to Sandringham to visit with Philip. The July 4th date wasn't convenient for the Archbishop or Canterbury either, but Harry's wife was hoping to substitute a female cleric and the Queen slapped her down on that demand, also.

The hoopla with a gospel choir wasn't for Lili, it was for Harry's wife. It remains to be seen what she has planned for Archie's birthday.

I'm guessing Diana's sisters were invited because she still doesn't have any Christian friends to ask to be godmother.

It was pretty funny when the media was speculating on who she would tap for Archie's godmothers, but when I checked them out on Wikipedia, they were either Jewish, Jehovah Witness, or members of the Self-Realization Fellowship Temple.