#1
Its the 2nd chord of an Em blues progression.

Im currently playing it as:

e x
a 6
d 7
g 8
b 7
e x

Im guessing this is B7 maj/D#. as its the 2nd chord in a blues progression should this be minor? im not sure which sounds better.

im starting from em7, so need to be playing this around the 7th fret for economy of movement.
#2
A /chord means a different chord tone is in the bass. Bmaj7/D# would be a first inversion chord with the third of the chord as its lowest tone. Thats about it.
#3
This is how I would approach it: (just so you know my strings are up the other way from the way you wrote them)
Em7
e 0
b 3
g 0
D 2
A -
E -

B7/D#
e 2
b 0
g 2
D 1
A -
E -

But there's heaps of ways to approach it.
Si