The products used to monitor and visualise the queue manager's objects like channels and queue depth don't need to change just because you are using RDQM. You can continue to use the same products that you would have previously used to monitor a single instance stand alone queue manager.
If you want to monitor the status of the RDQM cluster itself, you can only do so by issuing commands on the machines locally, so standard MQ monitoring tools that use the command server cannot help you there.
What tools do you currently use? Also, your question explicitly asks for "IBM products". Is there any particular reason why the tools need to be from IBM? There is a large and vibrant MQ community of vendors supplying configuration and monitoring tools for MQ. Are you able to consider those too?
Undoubtedly, nothing is ever as straightforward as it should be :-)
For monitoring solutions that used an agent, I would expect it to run as a SERVICE object using CONTROL(QMGR) if there needs to be only one of them running where the queue manager is live. Alternatively, I expect agent based monitoring tools might also be happy if you run an agent on every machine that the queue manager could be running on, and cover it that way. Certainly a question to ask of the manufacturer of the tools doing this.
For monitoring solutions that use a client MQ connection to the queue manager, then they can either connect to the floating IP address that will likely be configured with your RDQM cluster, or if you haven't got one of those (it is optional), then you just need to use an MQ Client connection technology that can cope with different possible IP addresses for the queue manager such as a CCDT or a comma-separated CONNAME.
Since I count as a tools vendor rather than a user in this regard, I will leave others now to give you their experiences.