I would push back on 7 and 8, and say footnotes shouldn’t be part of your slides at all. Those are for documentation and reference materials you hand out, not the slides during the presentation. Avoid any incentive to look at something other than the screen.
I would double down on 9. Presentation flow is absolutely number one. Looks don’t matter much at all. I only use simple black text on white backgrounds, inverting it for impact. Nothing fancier.
I just assumed 5 and 6. If you ever have to go back to a previous slide, I just thought you made a mistake and forgot something. Planing to do that is just kind of insane. And yeah, people with poor eyesight should be able to read it from standing against the back wall.