Major 7th open chords
The Bmaj chord is actually Bmaj7. I have checked several references and this is the correct fingering for this chord.
Major 7th open chords are again very similar to dominant 7th. The difference here is that the major 7th follows the major scale identically. If a C major scale is: C D E F G A B C, Root = C, 3rd = E, 5th = G, 7th = B. If you notice in a dominant chord B is flat, but not here so don’t be confused. Very slight differences make huge changes.
You will usually see these chords written just as they are above.