What would someone claiming to be the 2nd coming of Christ have to do...?

Just the usual stuff. Empty the weapons lockers, feed the hungry, clothe the naked, cure the ill, ensure justice ; ALL AT ONCE, ALL AROUND THE WORLD, WITH A WORD.

fulfil the tasks set out for the Messiah in the Bible:

http://www.chabad.org/library/article.asp?AID=1008...

But not perform wonders or tricks (or special effects) as this is proof of a false prophet and a false messiah:

"If there should stand up in your midst a prophet or a dreamer of a dream, and he will produce to you a sign or a wonder, and the sign or the wonder comes about, of which he spoke to you, saying "Let us follow gods of others that you did not know and we shall worship them! do not hearken to the words of that prophet or to that dreamer of a dream, for G-d is testing you to know whether you love the Lord your G-d with all your heart and with all your soul."

[Deuteronomy 13: 2-4]

not pay taxes for 10 years and get away with it.