The solfedge in a D major scale goes like this:
Do (D) Re (E) Mi (F#) Fa (G) So (A) La (B) Ti (C#) Do (D)
For accidentals, any added sharp would change the vowel to an "i" and any added flat would change it to an "e" (except for Re, which would become Ra).
Because B is La, Bb would be Le
Hope this helps!! =)
B-flat
A-flat Major scale
2 flats B-flat and E-flat
A flat minor is the relative minor of B major
No such major has b flat and e flat.
The subdominant in a scale is the 4th, which in the key of B-flat major is E-flat.
The mediant of B flat major is D.
In fixed "do" solfege, B-flat would be "tay"
B-flat
Eb Major
Relative major and minor share the same key signature but a different tonic note (a tonic note is the first note of the scale or in solfege tonic is DO). For example, D flat major has five flats in it's key signature and b flat minor has 5 flats in it's key signature; therefore, D flat major and b flat minor are relative.
A-flat Major scale
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 mediant is the 3rd of the scale, so in B-flat it's D.
B flat C D E flat F G A B flat
b flat, c, d, e flat, f, g, a, b flat
Eb Major