What is the proper procedure to request (my ex) to file her answer, which includes financial affidavit and proposed parenting plan?

If the 20 days are up for her Answer, I would file a Motion for Judicial Default so that the matter will come up before the judge again. I would also file a Motion to Compel her mandatory disclosure which sounds like it may be overdue. This disclosure includes her financial affidavit. There is no requirement for her to file a proposed parenting plan but you may want to ask the court to send the two of you to mediation.