You should study up on the 613 mitzvot. Even Jews don't keep all 613 mitzvot. When you exclude all the laws that pertain to the land of Israel, pertain to the temple, pertain to women, etc., etc., you're left with 278.
I've studied it. According to the website I listed, look under "Marriage, Divorce and Family." Only 4 have been deemed negative out of 23 laws. Doesn't look like all the ones that apply to women have been excluded to me.
Let's apply your argument though that only 278 are left. That still doesn't match the number of commands that Jesus gave us that He said would help grant us eternal life.
Concerning non-Jews, Rabbi Yitzchak Ginsburgh explains the problem like this:
For a non-Jew, spiritual "rectification" involves the refinement of the seven innate powers of emotion through a commitment to fulfill the seven Noahide commandments. The non-Jew's innate first nature is thereby transformed into a second, rectified nature, which enables him to "see through" the three uppermost levels of his soul and envision the "One." This (often sudden) perception causes the seven emotive powers to serve the three Divine powers, rather than the other way round.If a non-Jew neglects his obligation to observe his seven commandments, he remains unable to apprehend God's true unity, and his consciousness is apt to fall into idolatry, with its deluded worship of the "three"...