NT5 can inherit certs from active directory or any LDAP dir. No to private keys stored in remote location. MS can deliver only Windows stuff until November '99. Terminal servers will be integral to NT5, pervasive. No, if you have permissions to see that data.
Permission are on a per-item basis.
3rd party products will be many. Use batch scripts to populate databases. Not much, some tools, command line stuff. Yes, but not in beta2. Yes, by user.