I mean, 1 and 2 are truly brilliant points and certainly something I advocate in a counselling context as well as when interacting with friends. Even 3 is great, it's easier to accept 'I'm cooking dinner, mind if I bring some over?' than ask for help. I just think placing all of this emphasis on people not messing up when they're probably already trying to do their best is a tad damaging.
When someone has died you love, you can feel people pulling away. Not so much in my case because I'm lucky enough to have super supportive, close, open friendships and my friends were utterly fking perfect in every way imaginable. But in the cases of many other people I've spoken to, they feel something of a social pariah. They might have lost their partner, so they're suddenly the odd one out in their coupled up friendship circle, the awkward one at a dinner party, the one who's unsure of who their +1 will be at an event, the person turning up alone to parent's evening. I've even heard of widowed women losing female friends who suddenly become wary of having a single woman in their group who may pose a threat to their marriage (yep, seriously).
People don't know what to say so they just say nothing, or avoid. They go for the 'let's distract them' route leaving the grieving person feeling as though they can't sit and talk about the person they lost for fear of bumming everybody else out. Quite often they're the ones having to put on a brave face for their kids, their remaining parent, or whoever. It's just good for them to know that you are the person they can go to to speak about how they're coping and how they're feeling.
I'd rather people make the effort to talk to the individual even if they risk saying something that doesn't go down well than be so scared of messing up that they say nothing at all. I know you're not openly actively suggesting people ignore their grieving friends, but frightening people away from interacting with them by pointing out the already very obvious would have that exact effect. Can you see that?
You had some great initial points but by diverting into the 'please, remember, respect sensitivities and walk on eggshells' thing was just... weird!