Is is my understanding that domain name forwarding is not subject to "outages": servers can have outages, and websites can be down, but the forwarding itself cannot be down, as this is simply a pointer. (Or, the entire registrar where the DNS settings are hosted would have to malfunction. Is this correct?
Domain name forwarding is subject to outages just like any other hosting. Here is a list of steps that happen when somebody types in a domain name (forward.exmample.com) that gets forwarded (to www.example.com):
Outages could happen at the DNS level or at web host level. Here is what happens for a similar request for the correct domain. As you can see there is not much difference:
The biggest difference is that forwarding is a very simple type of hosting.