PACER is the federal judiciary's online system for searching dockets and documents from federal district, bankruptcy and appellate courts.
Yes, there is a small per-page fee with a per-document cap, and low usage in a billing period may be exempt.
They list addresses, employment, debts and property transfers under oath, which can help place people, though hardship is not evidence of wrongdoing.
No. A complaint states one party's allegations; only court findings, judgments or admitted facts establish what a court decided.
Ask the court clerk; many closed paper files are stored at Federal Records Centers and can be ordered by case number.