There are two rather narrow sets of stairs to go down into the venue. However, once you are in the venue everything is on the same level and you do not need to climb any stairs until you leave. The stage is not very high so it could be difficult to see the bands from the back. But the room is small, so you would be able to see something
The bathroom is adjacent to the room where the bands play. The toilet is a western-style toilet so you can sit down. The bathroom is a moderate size.
1-1-12 B1F, Minamisenba, Osaka, Japan