here ARE SOME possibilities why the 4th choose naruto:
1. he had no choice
2.hokages makes sacrifices
3.naruto has something in his chakra that can withold the kyuubi
the sealing jutsu of the forth is somewat different from the other sealing jutsu
here we can see how it is so unique because you can use this jutsu to seal something to oneself
then if thats the case, why is it that the 4th sealed the kyuubi to naruto?
1st possibility he has no choice
this is somewhat possible connecting it to the 2nd possiblity that the hokages makes sacrifices. so my point is why seal it to naruto if he can sacrifice himself to seal it to ones self ryt?
my theory is the 4th is not a candidate for sealing the kyuubi because if the 4th really might die with the sealing jutsu the kyuubi might escape from the seal
here the kyuubi warn sasuke not to kill naruto or he will end up regreting it
my theory is that the kyuubi might got out from the seal if naruto will die
well take it to the third possibility that naruto is the perfect candidate for the sealing of the kyuubi
here we can see that an ordinary person if got contact with the kyuubi's chackra is acting like a poison and amazingly naruto can endure the demon's chakra.
here yamato saying that naruto's chakra has the power to endure the kyuubi's chakra
my conclusion is that the forth didnt really have no choice but he really did it on purpose with his will to seal the kyuubi to naruto bECAUSE no clan may ever resist the kyuubi's chakra
hope you like it hehehee
ill try to look for more evidence to support tihis hehehe