Sorry, I don’t have any short term plans to add such an option.
As Rumo has pointed out, they’re somewhat unrelated, and I suspect users will be reaching for ‘merge notetypes’ more often than the other settings, which is why I thought it made more sense on top.
A heads up that addons-failed-to-load2 needs to be updated to match the latest English
I’ve added brief mention of it to the manual. Learning steps over a day are already warned about inside the deck options; I’ve added mention of clearing out custom scheduling.
alpha2 doesn’t support it properly either. Please wait for AnkiDroid 2.17 alpha3.
Great! Thanks for letting me know.
If you’re confident they’re a bug, dropping them directly on GitHub will save me some time 
The manual entries are ignored, so this is treated like a card with no revlog. We infer the stability based on the current due date, which is 2123. If we did otherwise, cards with missing history would get reset to new.
Maybe in the future. We’d still need to add a plus if the name wasn’t unique after adding that text.