Well, it is up to the ISP for all the above you are asking for. And they all lie about the bandwidth to user ratios, so we cannot get a good feel for the contention.
Some ISP's use traffic shaping, others do not.
The whole implemetation here is pretty chaotic. Most do not have firewalls on thier networks. Some that do, have it wide open to thier clients connection. Some block UDP, flat out. Some block ICMP (yes, the entire message list). Some block ECHO's only.
Quite frankly, it is a wonder it works at all. Every ISP has its own set of rules and configuration they run.