#1
So it goes;
C D E F G A B
1 2 3 4 5 6 7

And also;
Tonic, Super Tonic, Mediant, Subdominant, Dominant, Submediant, leading Tone.

And also
Root, Major 2nd, Major 3rd, Perfect 4th, Perfect 5th, and what are the 2 that come after that?

And why are there so many names for naming the notes in the major scale?
Would it not be easier to just call them their letter names and also their numbers?
#2
i think dominat etc is the description of the exact tone in a key and the other "major 3rd etc" are the names of the interval between two notes.

so its not the same thing.
#3
In a major scale, you'd have a major sixth and a major seventh. The terms (tonic, dominant, leading tone) are used to that you can talk about intervals and progressions without using actual notes. Each note in a scale serves a harmonic function, and these function are often described by the name, ex. the dominant pulls back to the tonic in a progression, the leading tone in a melody. This is simplified, but hopefully makes sense.
#5
Root, Major 2nd, Major 3rd, Perfect 4th, Perfect 5th, and what are the 2 that come after that?


in major scale

Major 6th
Major 7th

If you took all the intervals from some root (like C) you'd have this:

unison (C)
minor 2nd (Db)
major 2nd (D)
minor 3rd (Eb)
major 3rd (E)
perfect fourth (F)
diminished fifth (Gb)
perfect fifth (G)
minor 6th (Ab)
major 6th (A)
minor 7th (Bb)
major 7th (B)
octave (C next octave up)