For any part of the salt water hobby, the first and most important thing to learn is patience. Haste makes waste, and that costs money as well as the lives of livestock.
That applies here also when asking for help on forums. Many hobbyists don't have time to visit daily, some only visit maybe once a week.
Many that do visit, don't have the answers to specific questions and therefor don't respond to some questions.
For faster replies you would have to pose the questions on forums where more seahorse people frequent.
I'm not sure why the urgency at this time when you have stated that it will be some time before you proceed in setting up for this.
You might consider treating this research like a college project and use resources you would need in finding out information for a college paper.
All the questions you ask can be found by using the search buttons on the forums, going to the F.A.Q.'s pages, going to article pages, and using Google, just to name a few.
There is also a reef keeping magazine connected with this site with excellent archives from when a lot of extremely knowledgeable people were writing for the magazine.
Reefkeeping Magazine
I personally don't have any experience with macro in a seahorse tank so I can't help with that topic.