No. Even if you agree on everything, you have competing interests and the Law Society of BC says that lawyers can’t give legal advice to both parties on the same family file.
I can only be the lawyer for one of you. The other party would be advised to review the agreement with their own lawyer before signing.
When I’m the mediator, my job is to help people decide what’s going into their agreement, which I can write up. But as a mediator, I can’t give legal advice to either of you, and can’t witness the agreement.