One problem I see is all your devices are wireless, even if pfsense puts traffic in lower priority its already went over your shared wireless network.
Not sure how well that would work.
Wouldn't it be easier to just set your p2p (why anyone would do that over wireless in the first place?) to throttle down or just pause at night. Pretty much any p2p client I have ever looked at has a scheduler built into it, so say after 5pm pause, then resume after bedtime.
edit: So here is part of the problem of running p2p over wireless. Wireless is SHARED, only really 1 device talking at a time. So with p2p there is traffic even when your not downloading or uploading anything. Once you have joined a swarm or two, your going to be seeing traffic to your ip and port be it your actively running your p2p client even. Now have you forwarded your ports on your firewall for p2p? So that unsolicited traffic gets sent to your p2p box right. Well that is all traffic eating away at your shared wireless bandwidth. Now it might not be a huge amount, but it is still traffic taking up "shared" bandwidth
so I turned on logging for just a couple of seconds on my p2p forward on 43212
pass Jul 7 08:07:53 WAN 77.31.49.71:30700 192.168.1.8:42312 UDP
pass Jul 7 08:07:43 WAN 87.16.223.199:63782 192.168.1.8:42312 UDP
pass Jul 7 08:07:41 WAN 109.254.1.15:64355 192.168.1.8:42312 UDP
pass Jul 7 08:07:41 WAN 201.76.108.87:33911 192.168.1.8:42312 UDP
pass Jul 7 08:07:40 WAN 176.32.4.140:36355 192.168.1.8:42312 UDP
pass Jul 7 08:07:37 WAN 193.151.106.142:1027 192.168.1.8:42312 UDP
pass Jul 7 08:07:33 WAN 78.34.146.138:55016 192.168.1.8:42312 UDP
pass Jul 7 08:07:33 WAN 95.96.26.78:27581 192.168.1.8:42312 UDP
pass Jul 7 08:07:29 WAN 85.243.118.210:57270 192.168.1.8:42312 UDP
pass Jul 7 08:07:29 WAN 77.85.164.13:23640 192.168.1.8:42312 UDP
pass Jul 7 08:07:21 WAN 128.71.69.106:63151 192.168.1.8:42312 TCP:S
pass Jul 7 08:07:19 WAN 41.99.20.19:13383 192.168.1.8:42312 UDP
Why not run your p2p box on a wire, so that traffic does not eat up your shared bandwidth.. And then sure put it in a penalty box so it does not eat up your inet connection. You have 10 that you mention devices all sharing "shared" bandwidth. Are your devices all N, the Cells for example? If not - they are sure not helping either - its shared bandwidth, putting slower speed devices ie B on G, B/G on N only slow it down.
You have some box moving packets at G speeds - since its shared, you can not at same time have data moving at full N speeds, N is going to see something slower than if it was only N devices.
So I wonder is it your isp connection that is saturated, or is more just wireless bandwidth issue?