we have 8 internet connections with different ISP (two lines of them are of the same ISP), with different speed, some with dynamic IP via PPPOE, some with static IP
we also have a /29 subnet.. one of those IP I have used on wan interface of pfsense
pfsense has a public IP on it, ie not rf1918 (10.x.x.x, 192.168.x.x, 172.16-31.x.x) on its wan?
yes
And this is the same ISP that your other router is dynamic wan IP?
no