Don't worry, the experts might not either,... every few years they change their views, i guess we will never know for sure till we can observe one closer.
1) Does infinite damage at centre.
2) The nine surrounding squares do 200 damage (maybe for stars as well).
3) The black hole doesn't drag ships in, but also it isn't visible.
4) The system is called a normal system, and maybe some planets might be present on the fringe.
(and noticable players might ntoe the lack of stars at the centre of the map.)
1) is good
2) the 8 surounding squares doing 200 damage sounds good, but for a star, you should have the star's square only do the 200 damage, with 50-100 on the 8 squares around it.
3,4)Black holes are really easy to detect when you're close (astronomically). If you're in the system, you'll notice a star's worth of gravity plus a great accretion disk in many cases. If you're plotting a course, you will definitely notice whats happening.
Planets are perfectly OK, as long as they somehow survived the creation of the black hole (likely creation: supermassive star dying)
Maybe asteroid belts that can be formed into planets?