IP addresses are assigned not to physical ports(where you plug in the Ethernet cable), but to computers' network interfaces (think of them as network cards).
Looking at your router's spec it is clear that there is one physical WAN port RJ45 and 4 LAN ports RJ45 and of course WiFi. So the router itself has 1 WAN interface - the IP address on that will depend on your ISP - usually automatically assigned by ISP servers. This will be the one "outside" address of your network that can be seen from internet, which you will check say by http://whatismyip.com. The router also has 2 LAN interfaces - a WiFi interface and a LAN interface, bridged. This will be the one "internal" address of your router - usually set to some private IP such as 192.168.1.254. Although there are 4 RJ45 ports, you can think of them as a simple switch between your router and the rest of your LAN; there is one LAN address for your router, not 4.
What your commands seem to do is to set up some sort of quality of service setting so that certain traffic from some computers can be prioritised, but not assigning different external addresses to your computers. The "external" world will still see one address - that of your router's VAN interface and the router itself will translate addresses internally so that correct traffic ends up on the correct local computers. Unless you want to restrict/shape traffic for your LAN there should be no need for you to set anything via telnet. If you do - then go to Traffic Manager (page 28 in manual) and set up things as needed.
If for administrative purposes, includiong QoS you want to have static addresses on local network - you set them up on each local computer. You only need to see that the addresses fall in the same subnet as your router's internal interface IP. For example - if your router's internal address is 18.104.22.168 with netmask 255.255.255.0 (sometimes expressed as /24) then any address different for each LAN computer ranging from 22.214.171.124 to 126.96.36.199 with the same netmask should be fine. You of course would need to supply default route address (188.8.131.52) and usually the same will serve as your DNS server. With DNS however you can use google's 184.108.40.206 or 220.127.116.11
So to me, unless I have totally misunderstood, it seems there has been a little confusion in concepts and I hope this helps to clarify it. DD-wrt has a really nice interface and setting it up also helps with networking concepts. The danger of bricking always exists, but it is small and precautions are explained on their site.
Interesting, I looked this up. It apparently is called 1:1 address mapping. The idea is that you have a block of real/public IP addresses that your ISP knows to forward to your router, which then does the trick - also called 1 to 1 NAT or address mapping. Essentially it is about setting up firewall rules (which is likely what your commands in pastebin did). However you have to own those addresses - so that your ISP can forward those to your network. You can read interesting info here:
and also here:
And this is likely exactly what you need from DD-WRT:
I have used their firmware and have been very happy with the results. I did buy cheaply on e-bay a linksys router which was known to be compatible with it.