There is nothing special whatsoever about public IPs. They are just IPs that don't need to be NATted when being routed out to the Internet. However, just like with any private IPs you would use, they have to be available right on the Hotspot interface. They must be behind the router and routed through the public IP on the WAN interface, and not just be available on the WAN interface itself.
In that scenario the ISP's gateway is 126.96.36.199, your WAN IP is 188.8.131.52 and the world knows that 184.108.40.206/24 is reachable via 220.127.116.11. You assign 18.104.22.168/24 on an Interface, run the Hotspot wizard (or set up the pieces manually), and remove any NAT inserted by the wizard if you used it. You also need to remove any IP pools assigned to the Hotspot server profile as they are used for universal NAT (a Hotspot trick to make clients with misconfigured interfaces work) as that would waste a large number of public IPs.
I've done this many times, it works out of the box.
OK, I have to apologize as I think I may have mislead on my original post.Sometimes. Really, DHCP is irrelevant to the question. A DHCP server doesn't care what kind of address it hands out. It doesn't have a concept of private and public IP addresses. It's all just bits. The only thing special about private IP addresses is that most Internet routers are configured to drop them so that they can be used at lots of places at once without clashing with one another.
Hotspots with public IPs really just work out of the box as log as you treat them the same as you would with private IPs - just make sure you really are not using NAT, which the wizard will by default. I don't know what kind of problems you are having that haven't been discussed in this thread yet. Post your actual configuration and a network diagram if you are having further issues.
To limit rate for hotspot clients, use /ip hotspot profile set <profile> rate-limit=1. How do I get download/upload rate limited for each client if I set them on IP bindings? It will work adding them after that as simple queues?
If depends on which you specify. If you provide both IP and MAC, then client must match both. If you provide only IP, then client must match on IP. If you provide MAC with IP=0.0.0.0/0, the client must only match MAC.2. If I set on IP bindings both IP and MAC for an user, the user will be forced to use that IP and MAC or just MAC?
I would think this should be fine. A /24 allows 254 usable client addresses. If you don't exceed this, you should be ok.\3. Should I set more subnets on my configuration? (now I have a single subnet /24)