When we talk about the "constellations" how many of these use to be part of the 12 of the "zodiac"?

In 1920 the International Astronomical Union defined the boundaries of 88 official constellations. These include the traditional 12 zodiac constellations, although a 13th constellation, Ophiuchus, occupies a fair length of the ecliptic (the solar system's equator). You're correct that we can see most of these 13 constellations most of the time, except for the two or three close to the current position of the Sun. At the moment, the Sun is in Aquarius, so the constellations Pisces, Aquarius, and Capricornus are all hidden by the Sun's light. The constellations opposite these three are the ones most readily visible around midnight at the present time: Cancer, Leo, and Virgo. As the Earth moves around the Sun, the Sun appears to move through these ecliptic constellations at one constellation per month.