Like most Japanese names, they don't have an intrinsic meaning. It depends on the (many) combinations of Chinese characters they can be written with.
Michio:
道雄 ("way" + "man")
通夫 ("authority" + "man")
導男 ("guidance" + "male")
三千夫 ("three" + "thousand" + "man")
美智男 ("beauty + "wisdom" + "male")
Shin'ichi
真一 ("true" + "one")
真市 ("true" + "market, city")
信一 ("belief + one")
進一 ("progress" + "one")
新一 ("new" + "one")
慎一 ("humility" + one")
and many more examples.
~ isla, sophie, embla, zephyra, vida, clementine, swanhilda, calliope, magnhild, salomé ~
~ rémi, archer, louis, aurelian, pollux, lucan, storm, henry, nicodemus, maximilian ~