You have received some excellent advice, LeeLee, and I especially think that you should stick it to her with her daughter's behavior. I would be be tempted to say something like.......How come you have all of this advice to give me when your own daughter doesn't know how to behave in my home? That would be rude, but this woman crossed the line long, long ago.
I would also like to remind you of the Miss Manners standards of ........How kind of you to take an interest in my personal business, and.....How kind of you to say so. I would say these things in an increasingly peeved/sarcastic way as an event progressed.
Perhaps these would keep her in line after an initial confrontation, if you still want to have anything to do with her.
I don't think retaliatory rudeness is the answer here. If someone is rude to you in your home, you are free to ask them to leave. No need to snipe right back at them.
I agree but i think there is a non-rude way to do this. When she points out a flaw in yoru home/parenting/whatever look at what her daughter is doing and instead of responding to her snark, comment on the daughter.
BP: Your floors are too shiny, you need to fix this someone will slip!Response: Please get your daughter's shoes off the upholstered chairs
BP: You need more room around your toilet, your bathroom is too crampedResponse: You daughter may not chase my cats like that, they are live beings and they live here, she needs to respect them
BP: Colic Cure is no good, you need to use the Rx stuff I used!Response: your daughter is not allowed to open the china cabinet, please keep a closer watch on her
Basically make it like you are too distracted to hear her bossiness because you are too concerned over her kid.
Alternately on a totally different method I think you are welcome to invite her to not partake in things she complains about. just breezily and with a smile excuse her.
BP: Your floors are too shiny, you need to fix this someone will slip!Response: Oh you can just wait out on the patio if you are concerned, we won't be long, just finishing up our coffee
BP: You need more room around your toilet, your bathroom is too crampedResponse: No problem, there is a diner about a mile down the road, you are welcome to use theirs
BP: Colic Cure is no good, you need to use the Rx stuff I used!Response: well I would certainly never ask you to use my remedies, so no problem