I wonder if the distance of a pedestrian crossing from the centre of the roundabout relates to pedestrian safety. Subjectively, I feel like safety could be improved by moving the crossings farther from the centre.
Regarding your second point, if you mean a car changing lanes from an inner lane to an outer lane, it does need to yield to everyone in that outer lane. This includes yielding to cyclists whose trajectory would intersect with the car. Again, the same applies to all traffic.