𝟏. In astronomy (as opposed to astrology, a pseudoscience which was often proven wrong), we don’t talk about “north” and “south” nodes, but about “ascending” and “descending” nodes.
𝟐. The first two images and the fourth one show the Earth’s orbit as too tight a curve; this is what makes you have a hard time understanding. Since they come from astrology-related sources, I’m not surprised they can’t be trusted.
𝟑. The ascending node is the place where the Moon crosses the apparent yearly path of the Sun (the “ecliptic”) from the south to the north; the descending node is where the Moon crosses the ecliptic from the north to the south. This is the only proper definition.
𝟒. As JohnHoltz correctly stated, the intersection of two planes is a line, so ascending and descending nodes are indeed at 180° from each other indeed, as the third, fifth, and sixth images show. (Actually, the difference is not exactly 180°, because gravitational perturbations make the orbit, an ellipse rather than a circle, slowly turn with respect to the fixed stars. Hence, the line of nodes makes a full 360° turn in about 18.61 years. By the time the Moon reaches the next node, it has thus advanced a little [by about 1.5°, from a quick calculation]).