Jill
It is certainly possible to configure and run both Remote Access VPN and Site to Site VPN in the same ASA. And it is possible for the Site to Site to support split tunneling.
I am not sure about the part of your question asking about address pool since a site to site VPN does not usually use an address pool. In Site to Site VPN each site manages their own addresses and part of what you need to do for Site to Site is to configure an access list which will identify the traffic to go through the VPN and to be protected by IPSec.
HTH
Rick
HTH
Rick