Im seeing similar issues. My vpn clients can reach the internet no problem, but for whatever reason can't reach ony of the clients hanging off from switch0 interface. I tried with addresses both within the the same subnet as switch0 as well as a different subnet.
Don't worry about not seeing a DHCP lease for the PPTP/IPSEC clients. PPTP does not rely on DHCP, it will manage IPs on its own and these addresses won't be visible on the DHCP leases.
but I am also going a bit crazy as which routing table the packets coming from the tunnel are hitting... its weird.