1. 5♥-5♣, could be more, 1NT is usually 4♥-5♣ if you use it as takeout. 2. Yes, takeout, at least 4-4 in the others. 3. No, though 18-19 does x and then rebid NT. It shows the same two suiter as above, except not really limited. 4. Takeout, same minimum strength, unlimited maximum strength.