Using two NS dynamicly not possible ?

[rsmithgs]

I wont be able to answer all your questions but I will try to answer some :-)

I'm assume by dynamically you mean:

When a new domain is added to the ISPCP control panel that ISPCP will not directly update NS2?

If so then I think your right (unless someone has managed this) which is why people usually syncronise their slave with their masters every x amount of time. This doesn't need to be done manually as it can be scripted and then a cronjob set for the script to run.

This can be achieved with rsync or even using apache and wget (http://vhcs.puuhis.net/wiki/index.php/Secondary_DNS)

As for the second IP that ISPCP asks for, isn't this just so the NS1 DNS records are added with a NS2?

Hopefully the above goes some way of helping you out?