not quite sure about the bt4 one.
<snip> stuff that didn't matter </snip>
As for the third one, I have (or used to, inactive right now) an all-in-one-pet-special-action-button.
It went something like this:
What it does is Felstorm if FG, Whiplash if Succ, Singe Magic if Imp on yourself unless your target is friendly, Spell Lock (on focus if mod is pressed and target is hostile, else on hostile mouseover or hostile target), Devour Magic (same as Spell Lock, just helpful instead of hostile).
/cast [pet:Felguard]Felstorm;[pet:Succubus]Whiplash;[pet:Imp,help,nodead][pet:Imp,@player]Singe Magic;[mod,@focus,harm][@mouseover,harm,nodead][harm,nodead]Spell Lock;[mod,@focus,help][@mouseover,help,nodead][help,nodead]Devour Magic
No Voidwalker in there, but I have him out next to never.
Something similar like your proposed macro for whiplash isn't possible, because whiplash has no target, but that green circle thingy (which will just come up if you press that macro).
Hope that was of any help.