Who messes with funeral plans, you ask?? Lots of people do! Death brings out the best in people, but unfortunately the worst in people also. My grandfather passed away suddenly a year and a half ago, and we went through holy hell with my aunt who insisted that she was going to determine what the funeral date was going to be. My GF's wife is the one who does that. My aunt of course picked a date that my military brother, who got special, limited family leave from overseas couldn't make. And she refused to budge on the date no matter what because she said it would be incovenient to her and her family. When we asked what the inconveniences would be, she proceeded to tick off a list of very trivial, petty incoveniences that could of been accomodated with no great loss or disturbance to their family. Finally GF's wife put her foot down and said that it was going to be another date that everyone could make, and that was that. Aunt said fine, then my family will just not attend the funeral. So the whole entire family stayed home while the rest of us were there at the funeral because they couldn't get their frequent flyer miles for the trip. The absence was very noticeable, and people were confused and asking where they were. An event that could of brought the whole family together for support and fellowship together was somewhat marred by their absence. Now we're having serious problems with them over GF's estate, but that's a whole different story.
In your situation, I don't think that you have anything to worry about with this Janet causing any more problems. The funeral home has been clearly instructed to not listen to her about any changes and such. They're used to dealing with situations like this and know what to do. Believe me, I bet they have seen far worse situations. I don't know what it is about death that makes people like Janet, my aunt, and others act so horrible and uncooperative. I wish I knew so I could understand.