Thank you for your questions.
Amending a BK Schedules and a Chapter 11 or 13 Plan entails no additional filing fee. Motions get filed for free, too.
The second question appears to mix issues.
Objections to Plan confirmation can be made by any creditor or the Trustee
. An objection deals with the Plan, while an Adversary Proceeding seeks to exclude a specific debt from discharge.
An Objection's responsive pleading is an Opposition to it. It's an involved process and requires a genuine memorandum of law to support it. An opposition is required or the debtor will almost always lose by default.
An adversary proceeding requires a complaint by the plaintiff and the debtor is required to file an answer. Both are brief. The complaint will lay out parties, jurisdiction, venue, and claims, and the debtor/defendant's answer has for each paragraph of the complaint admissions, denials, denials, denials based on lack of knowledge, plus affirmative defenses, and maybe even counter-claims. An answer is required or the Debtor loses by default.