F major
F Major has 1 flat in it's key signature. Which is the B flat
There are different rules. For major keys, the rule is this (by the way, # means sharp): C major scale- 0 sharps or flats G major scale- 1 sharp - F sharp D major scale- 2 sharps - F and C sharp A major scale- 3 sharps - F, C, G sharp E major scale- 4 sharps - F, C, G, D sharp B major scale- 5 sharps - F, C, G, D, A sharp F# major scale- 6 sharps - F, C, G, D, A, E sharp C# major scale - 7 sharps - F, C, G, D, A, E, B sharp. For major keys with flats: F major scale - 1 flat - B flat B flat major scale - 2 flats - B, E flat E flat major scale - 3 flats - B, E, A flat A flat major scale - 4 flats - B, E, A, D flat D flat major scale - 5 flats - B, E, A, D, G flat G flat major scale - 6 flats - B, E, A, D, G, C flat C flat major scale - 7 flats - B, E, A, D, G, C, F flat So as you might have noticed, in increasing order of sharps it is: F, C, G, D, A, E, B. And the increasing order of flats is B, E, A, D, G, C, F. If you notice the order of sharps is the opposite of the order of flats.
Ab Major
F major
The mediant of B flat major is D.
F Major has 1 flat in it's key signature. Which is the B flat
D flat, E flat, F flat, G Flat, A flat, B Double flat, C flat, D flat. However, since D flat and C sharp are, essentially, the same, it would be easier to write in terms of C sharp. The scale would then read C sharp, D sharp, E, F sharp, G sharp, A, B, C sharp.
A-flat Major scale
The subdominant in a scale is the 4th, which in the key of B-flat major is E-flat.
C flat Major
e-flat major
Your question doesn't make much sense. But for any scale, "do" would be the first note of the scale, which is whatever the scale is called. But for a flat major, from what it sounds like you're asking, the note would be a flat. Ex: In B flat major, "Do" is b flat.
The Keys of B-flat, E-Flat, A-Flat, D-Flat, G-Flat, C-Flat, and F-Flat major all contain the note E-flat. F-flat major is a key which only exists in theory and not in practice, since there is a double flat in that scale (subdominant). The major scale with the most flats is C-flat major - with all seven flats.
Eb Major
if it's an A-Flat scale the first note is A-Flat...
The solfege syllables for the flat notes in a major scale are: Flat 3: Mi Flat 6: La Flat 7: Ti
There are different rules. For major keys, the rule is this (by the way, # means sharp): C major scale- 0 sharps or flats G major scale- 1 sharp - F sharp D major scale- 2 sharps - F and C sharp A major scale- 3 sharps - F, C, G sharp E major scale- 4 sharps - F, C, G, D sharp B major scale- 5 sharps - F, C, G, D, A sharp F# major scale- 6 sharps - F, C, G, D, A, E sharp C# major scale - 7 sharps - F, C, G, D, A, E, B sharp. For major keys with flats: F major scale - 1 flat - B flat B flat major scale - 2 flats - B, E flat E flat major scale - 3 flats - B, E, A flat A flat major scale - 4 flats - B, E, A, D flat D flat major scale - 5 flats - B, E, A, D, G flat G flat major scale - 6 flats - B, E, A, D, G, C flat C flat major scale - 7 flats - B, E, A, D, G, C, F flat So as you might have noticed, in increasing order of sharps it is: F, C, G, D, A, E, B. And the increasing order of flats is B, E, A, D, G, C, F. If you notice the order of sharps is the opposite of the order of flats.