pfsense is awesome, but it needs a bit of learning.
You need as a minimum a WAN port and LAN port, but a DMZ is also a good move. So does your laptop have two wired network interfaces? I doubt it.
I'm not sure how you could use pfsense on a Debian box. pfsense is a Freebsd based system in its own right. You can integrate a wireless card into pfsense.
How do you connect to the Internet? Is it PPPoE? If it is, you need a method of initiating the connection and passing your log-in credentials. It's not just about ports. How are you going to initiate a firewall? Maybe use Shorewall in Debian, but then you need to integrate the whole lot together - not for the faint hearted!
If you've just a cable modem, it just modulates packets to pass them down the line. In most cases of itself, it won't connect you to your ISP, so you probably need a router to carry out that function. Even if it uses a MAC address to identify you, you still need the ability to spoof the MAC address or re-register it.
In essence, I think your plan is flawed and it's not something I would attempt. The pfsense developers are high level and extremely talented and have probably spent hundreds of thousands of hours developing their solution. Can you hand on heart say you could match them? By your own admission, your Linux networking knowledge is "not very strong".
I've just initiated a new pfsense installation and it goes like this:
Cable modem --> pfsense box --> gigabit managed switch --> local network
and via the DMZ:
Cable modem --> pfsense box --> DMZ --> gigabit switch --> server(s).
I'm afraid you just have to grin and bear the power costs.