Requested WoW macro

Hello. :) #1 and #3 seem easy enough, but I have had troubles with them, not working properly. #2 seemed impossible.

#1 I would like a macro, that would instantly target a specific player when I am or am not in a fight, and cast one of the three spells. Eternal Flame – if it is available / Lay of Hands if targets health is below 75 000 hp / Flash of Light.

#2 I get tired of pressing all the keys on a boss, that does nothing to me, but takes a minute or two to kill… Is there a way to cast skills like ” 1,2,3,4,5 and afterwards it would cast any of these which activates the fastest.

#3 A macro, which casts Divine Protections when I use Judgement attack skill. But wouldn’t ”yell” that skill is not ready yet, when I again would cast Divine Protection.

#4 Not sure if it is even a macro, but would automatically cast lay of hands on me, if my health is below 50k.