Lot of info here but no facts from which any meaningful response can be provided. In mediation, there is nothing that requires either party to accept terms if they are dissatisfied. From your post, it is not clear if an agreement was reached at the mediation and if that agreement was thereafter written and then signed by all parties. If the agreement was placed on the record before the magistrate and consented to by the parties, it is binding just as it would be if a written settlement agreement was signed by the parties. If your magistrate is stating that there is no difference between "B" and "E" perhaps there is no difference. Whatever the case, you will want to consult counsel, provide facts and then get advice on how best to move forward.
The information above is NOT LEGAL ADVICE and you should not rely on it. Providing information on Avvo does NOT create an attorney-client relationship even if there is a back and forth exchange between us. The relationship can be created only if we both sign a written agreement and you have paid fees as required.
Your question is not very clear, but I will pick out some of it and answer what I can.
Def counsel drafting an agreement that differed from the agreement stated on the record and then changing it after plaintiff pointed it out does NOT count as bad faith.
2 weeks after mediation to prepare the written agreement is NOT excessive.
If Plaintiff agreed on the record, and is now trying to get out of the agreement, the defendant is entitled to try and enforce the agreement. What you describe is not sufficient to overturn a settlement.
The court, especially a Federal Court, will more than likely enforce the agreement that you entered into on the record. You may end up having to pay defendant's fees incurred in attempting to enforce the agreement.
It may now be a good time to stop representing yourself and talk to an attorney.
Order a transcript of the agreement on the record.
My name is Stephen R. Cohen and have practiced since 1974. I practice in Los Angeles and Orange County, CA. These answers do not create an attorney client relationship. My answers may offend I believe in telling the truth, I use common sense as well as the law. Other state's laws may differ.. There are a lot of really good attorneys on this site, I will do limited appearances which are preparation of court documents it is , less expensive. However generally I believe an attorney is better than none, but many will offer a free consultation and a face to face meeting generally will be better, I like my clients to write a short one page history of the fact and questions they have prior to meeting with them, so nothing is forgotten.