Why do I only see Bonjour services on my iOS devices?

So you can keep pounding your head against a device that you cannot get to work for your needs here and that you cannot get support for from the vendor's free-support forums, or you can switch your approach here and get a Cisco support contract for it (this presumes you can find documentation from Cisco that says this particular usage is supported or will be supported), or you can replace it with any of various other AP devices that do meet your needs.

If not as part of replacement, then solely as a test, please insert a different AP, and run your tests again. Test without the Cisco device. See if that configuration works. (Cisco has competition, after all.) That'll almost certainly tell you if it's the Cisco AP that's causing this, or if there's something else going on.

ps: I would expect the mDNS stacks of iOS and OS X to be based on the same code, FWIW.

Create a computer-to-computer network between two of the clients. If they see each other's Bonjour services, then you know it's a router issue, not a client issue.