You need, for your own health, to stand up for your talent and professionalism and take all the advise given and do what needs to be done, get paid what is due.
You do not need to confront her if you do not want to, let the lawyer do what needs to be done. If you have all your paperwork, pictures, email correspondence in order as proof, you have what the lawyer needs to proceed.
Why are you letting this person bully you? Get a backbone and stand up to her abuse. She is a liar and a thief and should not be allowed to do this to you are anyone that participated in the event.
Would you allow someone to steal from your children? Would you allow her to abuse your children? Would you allow her to put your children down in front of all her friends?
She knows you will back down if she stands her ground, so why are you letting her?
You came here asking a question and my answer is NO. This is fraud. She signed a contract not only with you, but the check is a contract and the contract was fulfilled. She had no legal grounds to break the contract. You do not help out yourself or any other cake artist by letting her get away with this.
If guilting you into action is the only way to get through, then this is my intent. Help other cake artist and take action so that the message gets through to those that want to steal.
Your cake is beautiful with or without the flowers. It is elegant and you should and must be compensated for it.
The easy thing to do is to let it go, but what will you do when the next customer does this, because they heard you let her get away without paying for a perfect cake?
Off my soapbox now. Good Luck