I don't remember ever being taught to use more than one exclamation mark at a time, and the same applies to question marks. Also, they should not be preceded by a space. Clearly you weren't taught very well.
Woofie (Google "I will or I shall") - "In traditional British grammar, the rule is that will should only be used with second and third person pronouns (you; he, she, it, they). With first person pronouns (I and we), the 'correct' verb to talk about the future is shall".
My primary school teacher taught us to have a space before them. It always looks wrong to have the punctuation jammed up against the word as if it were part of it.
As for multiple use. It may not be perfect English but it is common practice to use that to give emphasis, and that's fine as far as I am concerned.
bhg, that's only half the story. One verb expresses mere futurity, the other intention. So the drowning man says "I shall die, nobody will save me", the suicide says "I will die, nobody shall save me".
I put HGVs and TVs since the 's' isn't part of the abbreviation. I see the apostrophe as just jarring and unnecessary. But that's probably too sensible to be official.
Probably because punctuation without an ascender just sits on the line and has no visual perceived affect on the preceding word. Those with an ascender changes the image of the word as if it was misspelt or something.
Something I also dislike it the pretence that inanimate objects can't possess things. A door "owns" it's own doorknob; how dare the rules arbitrarily deny use of the apostrophe by some nonsense excuse ? Either possession is defined by 's or it isn't.