A few questions on the current PE draft

Upon re-reading the current draft, I have a few questions.

1. At any point in time, how many pointers can simultaneously have isPrimary
set to true? The way I read it, there could be up to three, one for a mouse
device, one for a touch input, and one for a pen input, if the underlying
platform supports all three input types simultaneously. Is that correct?
2. If my understanding in #1 is correct, then in "8.1 Mapping for devices
that support hover", there should be *three* different PREVENT MOUSE EVENT
flags, one for each input type. Otherwise, cancelling the pointerdown event
of the primary touch input would inadvertently disable the compatibility
mouse events for subsequent events from the primary mouse and pen inputs as
well.
3. In "8.1 Mapping for devices that support hover": 
[[ 4.If the pointer event dispatched was pointerover, 
1.dispatch a mouseover event, and
2.if the pointer has been moved onto the boundaries of an element or one of
its descendants then dispatch a mouseenter event.]]
Why not simply dispatch a mouseenter event when the pointer event being
dispatched is a pointerenter event, and only dispatch the mouseover event
with the pointerover event? I'm guessing that this is an artifact of not
having the pointerenter and pointerleave events initially?
The same applies to the pointerout event, as well as section 8.2.
4. In "7.3 Implicit Release of Pointer Capture", should the requirement also
apply to the firing of the pointercancel event?

Regards, Cathy.