Okay so I am going to assume (yes I know what they say about making an ass out of you and me) that "frosty" is your mage.
/assist elementall
/cast frostbolt


for the heal: you are not assisting frosty, you need to target him.
/target frosty
/cast chain heal

for the third example do a /castsequence

/assist elementall
/castsequence <spell 1>, <spell 2>, ect.


really your best bet is make the focus of your second toon the first toon though.