CA design Forest and subdomains

We have 1 Forest with an empty Forest Root Domain and 3 regional subdomains
for example:

The Active Directory structure for Fabrikam is a single forest with four
domains: fabrikam.com, americas.fabrikam.com, europe.fabrikam.com, and
apac.fabrikam.com.

We create an offline Root CA.
We implement 1 issuing/Policy CA.
All CA Administrations are done centraly in the HQ.

Q1) Should we place the Issuing CA for all Subdomains in the empty
fabrikam.com, or can we place the the Issuing CA in the europe.fabrikam.com
for all domains ?

Q2) where do we have to publish the LDAP location? in the forest root domain
container?

Thanks.