the 1st never beat him,madara just tricked him and took his dna.the 1st hokage could not beat him even when he tried to kill madara it was unsuccesful.
well, it seems the younger son survived the tailed beasts and infinite izanagi, so you reach your own conclusions. i'd guess he is like naruto is now, swatting away bijuu bombs like flies.
Yes, the 1st did beat him. Madara just didn't die like Hashirama thought he had, and Madara managed to escape with some of Hashirama's DNA.