Can I still request a DHCP address from Comcast on a router in bridge mode with statics?

Currently, I have a sub8 with my router is set to bridge mode. I have one port connected to my pfsense box dealing with the statics. If I connect another port to my freenas box and set it to DHCP, would it be able to pull an address from Comcast?

To explain, my son streams on twitch and I would like to route his computer to go out on a throw away IP instead of one of the statics.

I did hook up a linux laptop and tried it. I got an ipv6 address. Not really familiar with ipv6, so I didn't know what else I needed to configure on my side to get access to the internet. I also wasn't sure if the router itself was suppying it or it was coming from Comcast.

Thanks,

Anthony