No, a white dwarf is not considered a main sequence star. A main sequence star is a star that is still fusing hydrogen in its core. A white dwarf is the remnant of a low to medium mass star in which fusion has stopped.
No. Sirius is a two-star system consisting of a white main sequence star and a white dwarf.
Sirius is not a single star but a binary star system consisting of a white main sequence star and a white dwarf.
The sun is neither a supernova nor a white dwarf. The sun is a main sequence star. A supernova is not a kind of star: it is the explosion of a massive star.
Neither, it is a main sequence star.
white dwarf. unless you count black dwarf of which none have been observed, only theorized.
Assuming you mean a "main sequence" yellow star, it's a white dwarf star. In the end that fades to a black dwarf.
None of those is a main sequence star.
Pluto is not a white dwarf star, it is just a dwarf planet.
No. A dwarf star is a small star. A white dwarf is just one particular type of dwarf star, but there are other types.
Main sequence stars are bigger.
Depending on the size of the blue-white star it may be a white dwarf, a main sequence or even a supergiant star.