Are seahorses really as hard to keep as people say?
For some yes, for others no. It depends on the overall outlook and approach of each individual IMO.
Do they absolutely need to be kept in pairs?
NO!! They should not be kept as an individual though.
Is it true that they need their temp at around 74 degrees?
For tropical seahorses the recommended range is 68° to 74°F even though in the wild their temperatures will range higher. In the wild, the water is ever changing, but in tanks where it isn't, the bacteria growth can be deadly to seahorses with their weak immune systems. The nasty bacteria growth rate is exponential with each rising degree, but ESPECIALLY above 74°F.
The combination of keeping water quality up and restricting temperatures can go a long way to success. The water quality that promotes bacteria growth rate CANNOT be measured with any test kits (think dissolved organics for instance) so we need pro-active husbandry/water changes as opposed to RE-active.
There is a lot of info in the stickies at the top of the forum to glean information from, but in addition to that, the Facebook groups, Seahorse Sources Group and Seahorse Solutions Group each have a lot of info if you go to their pages and click on "MORE" followed by clicking on "FILES".
At lot has changed in the hobby over the 18 yrs I've been doing it, like the recommended tank volume, temperature, and especially tank flow rate. Unfortunately there is a LOT of this old info still floating around on the internet, which coupled with a lot of MISS-information can really make it confusing for new hobbyists.
No one thread will be able to give you all you need to know, but after you have done your research, you can be more specific in your questions to help you make better decisions.
There are a multitude of methods in use today and it's a case of finding what works best for you.
Starting up new, it's my belief that it's best to adhere to the KISS principal and once you've gained experience you will be in a better position to decide what you want for the long term.