To clarify, you have one inbound message from a service going to one process/routing rule with two sends in it. You've noticed that sometimes messages get sent not in the same order as they appear in the routing rule. 

If above is correct, try checking Force Sync Send in the process settings.

Generally, you'll likely have to write a BPL and use the delay action if you want to sleep/halt between sends. 

If you are planning to implement an interface with Kafka, I suggest reading the following:

https://docs.intersystems.com/latest/csp/docbook/DocBook.UI.Page.cls?KEY...
https://community.intersystems.com/post/ensemble-rabbitmq-java-client-qu...

When it comes to specific pain, there are just a lot of pieces to maintain compared to common interfaces, such as HL7, etc.
Also, if you plan to send a large volume of messages, you'll have to do that asynchronously. The problem with that is you may send 100 or even 1000 messages before you realize there is a connection or other problem. You'll have to think of a way to keep track of what messages have been sent successfully and which didn't, and requeue messages that have failed. Of course, if you are not worried about "losing" messages, that's not an issue.

Yes, it's possible to add the send where you want it.

You'll need to change your rule to look similar to this:

The problem with having two or more when blocks back-to-back is that they are bit misleading.   
You may assume that

when "condition 1"
    send
  when "condition 2"
    send

is the same as following pseudo code

if ("condition 1")
    send
  if ("condition 2")
    send 

when, in fact, it works at the following pseudo code

if ("condition 1")
    send
  else if ("condition 2")
    send

This means that when you have consecutive when blocks, one and only one when will be executed.
A workaround is to put each when block into its own rule.

P.S. I would split this routing rule in two separate routers and routing rules: one that sends messages only to EDM and one only to RIS. When you have a large environment, makes maintenance and a whole lot of other things easier in the future.

This typically means that the remote system has failed to send an HL7 ACK back within 30 seconds. If it is common for that system to take awhile to respond, you can increase "Response Timeout" from 30 sec to a higher value.

Your question is too broad to give a detailed answer. It's possible that you don't even need load balancing, or there is a better solution.

Maybe you could you tell us in details () what's your setup and what problem you're trying to solve?

I'm guessing you're looking at the Production Configuration page. Try setting the IP Address of your operation, and it will show up in the Operations columns. Without the IP set, it will be in the Services column.