I think you underestimate some of the Flat Earth people here. Because of their high standards of proof and need for you to show experiments that they can perform at home or can be performed cheaply on a large scale, you'll need to invoke a lot of science to debunk them.
They believe they've already addressed many of your points below (although their explanations were absolute junk). So all you'll get is some mean, snarky responses from them.
I'll just give some (not representative of all FE) arguments that I've heard against what you've said:
1. Waves / thermal inversion / atmospheric refraction
2. You'll see a curve because the spotlight is circular. See the High Altitude Photographs section of the wiki.
3. They always droop... This has nothing to do with the flatness of the Earth. If you're referring to undersea cables, a few FEs have asserted that the measurements weren't made to requisite precision to construct the appropriate quadrilateral to debunk the flatness of the Earth.
4. Or the stars could just be rotating above the Earth... There's no FE map so you can't be sure of where the observers are. Of course, if you get into the nitty gritty, this explanation quickly falls apart, but they won't hesitate to take you there.
5. No relevance to whether the Earth is flat. This is a bad argument put forward by FE that most here don't accept. Of course water can curve if you hold it there.
6. Nope. There's a shadow object blocking the Moon.
I'd be happy to play devil's advocate on debate.org against you to show that a lot of their arguments are far more cogent than you believe. Yet when you look at the physics, it all falls apart, because most of the arguments are premised on fundamental misunderstandings of basic physics. But they're not nonsensical.