Migrate from DHCP Superscope to VLAN Based DHCP Scopes

I recently started at a company using RFC1918 addresses in a large flat layer
2 network with one border router (1 primary and 2 secondary addresses on
fa0/0 along with EIGRP).

Before I started working here, their implementation method to accomodate the
500+ computers, was to setup a WIN2003 DHCP server with 3 DHCP scopes and
three NICs (one for each DHCP scope/network) and then run superscope. We are
part of a larger Active Directory Forest.

I've recommended we migrate to VLANS with a single DHCP server issuing
addresses for each of the separate VLAN subnets (we have Cisco devices, so I
will be using the ip helper commands).

I'm starting to get the feeling that the Windows Server Administrator does
not know Windows Server Operating systems very well (I'm kind of weak in that
area, but that's not my primary area of expertise), so I'd like to be able to
provide some help.

I plan to bring up the layer 3 switch and gradually migrate groups over to
the new VLANs using non-RFC 1918 address space (I don't have a choice, we are
part of a larger company and they are converting all branches). Once done,
we will stop using the current RFC 1918 addresses.

Two questions:

1. Can we keep the current DHCP/Superscope configuration AND create new
scopes using address space from the new VLAN subnets?

2. If we can't do question 1, what are some alternate options (maybe bring
up a temporary DHCP server to serve the VLANS until we are fully migrated
over)?