1. If you are not using undo/redo, an easy solution is to delete the new arrow in response to the ArrowCreated event. In that case you will know to which anchor point the arrow has been attached, and can count how many arrows are attached to it. Otherwise you can prevent that from the validation event RequestCreateArrow, but you will need some additional code to detect the nearest anchor point because it is not passed as argument to the event. I can send you some sample code if you need detecting the nearest point.

2. Set AllowRefLinks = false.

I hope that helps,
Stoyan