If you take standard cosmological assumptions (the universe is infinite and homogeonous) then the odds are 100% as everything that is physically possible happens infinite times.
unless you mean the observable universe, in which case we dont know, but given the vast scale of it is likely very close to 1. We cant calculate it without knowing how likely life is to form in the first place.
Its not true, but the only time a Republican presedential canditate has got a majority of the votes in the 21st century is GWB in 2004. In the 20th century the winner in every election was the one who got the most votes, D or R.