Virtual PC can´t get IP from DHCP (eve ng)

In the diagram, you definitely need a bridge in the hypervisor to simulate an Ethernet cable between the lan port of the virtual OpenWrt and the lan port of the virtual PC. You could also bridge it out to a physical port on the host machine if you have an extra hardware port. Configuration of networking outside the VM guest (i.e. in the host / hypervisor) is beyond the scope of this forum.