The exceptions I can think of to Rule 3 are cases where it's all right -- that is, the character in question was dead all along and this comes as a surprise to the reader. Off the top of my head, Yu Yu Hakusho starts off this way. A zillion movies use a similar device, with the "I was actually dead" as a plot device near the end. Then there's Vigarde/Monica in FE8. Her corpsehood (literally this time) was revealed as a twist to the player. So, yeah. Twain snarking.

I like rule 4, though. I think it presents a critical hurdle for anyone trying to novelize an FE game, which has a playable cast of anywhere between 20 and 72 characters. (FE10 is the one with 72, with the small proviso that one of those characters is only playable for two and a half chapters and not near the end, and another is a hidden character who's only usable on the very very last stage if you've jumped through a bunch of hurdles and it isn't your first playthrough.)