Exchange Server itself is not supported on 32-bit versions of Windows, but your DC/s do not need to be 64-bit. The data stored in Active Directory is not fundamentally different between 32- and 64-bit editions of Windows.
Yes, all of the commands should be run from the 64 bit system that you are installing exchange on. You must be a member of the Schema Admins group as well as the Exchange Admins group to do the AD prep work. If you are running the schema dn forest updates manaully they still need to be run from the exchange server and you still need the appropriate permissions to modify AD
Yes.
Exchange Server itself is not supported on 32-bit versions of Windows, but your DC/s do not need to be 64-bit. The data stored in Active Directory is not fundamentally different between 32- and 64-bit editions of Windows.
Yes, all of the commands should be run from the 64 bit system that you are installing exchange on. You must be a member of the Schema Admins group as well as the Exchange Admins group to do the AD prep work. If you are running the schema dn forest updates manaully they still need to be run from the exchange server and you still need the appropriate permissions to modify AD