Legal opinions state otherwise: https://www.scribd.com/document/443783939/OLC-Opinion-Judicial-Enforcement-Authority-01-19-2020
You wish to scrap basic checks and balances and a great many a bad precedents, rather than go though the proper process that would give us both what we are asking for. The House flubbed this so badly, it is hard not to think they did it on purpose.
Wrong again. He has never failed to answer a subpoena that was adjudicated as legal. The one subpoena that was brought to court, the House Democrats canceled before adjudication.
Nope. The President is allowed to claim Executive Privilege when it concerns his national security advisors. If the house disagrees, THEY have to go to court and get a ruling.