Malabo (never been there but saw it plenty of times from offshore Eket!)
1. The symbols are 'airports'. They are put there by the FMS regardless of the route. In fact, most of the ones you see are platforms that have been enetered into the company database as 'airports' to achieve just this. You can program the FMS to show what type of waypoints you want it to display: on my previous type that used this FMS it showed VORs. Obviously there is a FW biase to it, but by calling platforms 'airports' I think the outcome is quite successful.
2. Don't even get me started on that one! All legs are magenta, regardless of whether they are active or coupled. The active leg destination waypoint is magenta and the subsequent waypoints are white. Here's a great idea, if anyone's listening: make the active leg a different colour from all other legs, that way you can see at a glance where you are relative to it. Then, make it a different colour depending on whether you are coupled or not. Say blue uncoupled, and green coupled. Hey, then apply that convention through out: e.g. HDG bug "ah, it's green, I must be coupled to HDG" etc etc.
3. No, single middle ring for RADAR, multiple for ND. They both show the same outer range, but each pilot can select different ranges. The ND can also show a full circle; currently showing ARC (in double screen picture, you can see bottom left side of ND has two soft key functions: ARC is white background denoting active, FULL is black background, denoting available).