Your first list up to 5 is a good list of the things that need to be overcome (6 has some assumptions I don't find compelling and 7 is, well, unpersuasive

). However, I don't think that your 'let it work' bullet is particularly fair. The devs haven't actually answered on this particular nuance, and could say that this works without actually disagreeing with anything they've said before. IE, the prior could be the general rule while this narrow corner might be the exception that proves it.
I think Arial and seebs have put forth a great argument, and that the rules aren't clear enough to say they're wrong outright -- they might still be right. I also think it's a longshot that they are, merely because addressing this corner case in the way Arial presents would just add confusion and other possible corners that a flat 'nope, doesn't work, can't dispel instantaneous spells at all' won't. Sure, the latter leaves some odd holes in logical progression, but it has the benefit of being easy to apply and fair in the vast, vast majority of cases.