I am very confused after reading this thread. You say that you have done your research, but it is obvious that you simply have not done enough, or possibly have been doing research on the wrong topics. It seems that you are uncertain of what type of seahorses they are, and that should be adressed before anything else. there is no such thing as a "fu manchu" seahorse.... You also seem to be confused on dwarf seahorses... If you think they are reidi's then, they are NOT dwarf seahorses (which would be Hippocampus Zosterae).
It sounds like you have small H. Reidi's and you need to act according to the parameters of their care needs, and not those of the zosterae. If they are already 3-4 inches long, you can rule out that they could even possibly be dwarf seahorses, since at BEST the dwarves are gonna be about an inch long. Dwarf seahorses have completely different care requirements from the rest of the species' of seahorses and need to be dealt with accordingly.
You selection of tankmates is not an ideal choice for any type of seahorse. The angel and the blenny, specifically, both have tendencies towards fast movement and aggressive natures, and therefore make a poor selection for a seahorse tank. Aside from physical interactions between these fish and your seahorses, the biggest problem is that those types of fish will monopolize the food in the tank, unless you are very good at target feeding. Seahorses require different types of feeding than the fish that you are used to and you need to be aware and respectful of that. They will wait until the food comes to them, whereas your other fish will go after anything they can fit in their mouths, wherever it may be. The seahorses require more feedings than most other fish due to their lack of a stomach, and this has to be addressed in their care, which affects the feeding of these other fish, and your need of an increased cleanup crew to handle the amount of waste they produce, both from the feeding process itself, to the.. umm... "other end" of the process....
Since you obviously have one of the larger varieties of seahorse, which means you must have some younger specimens that will be growing up to 100% larger than they are currently, you really need to think about the future of your tank, and if you want the seahorses to be successful in the long term, you are most likely going to have to make some major adjustments to the:
physical setup
Hitching areas
Places with shade/sunlight
Zones of water movement
Feeding needs
your cleanup crew.
I have posted quite a few threads on here dealing with seahorse care, and websites such as seahorse.org, seahorse.com, wetwebmedia, sygnathid.org, etc would be big help to you.
I STRONGLY recommend revisiting your research, getting a definitive ID on your ponies (posting a pic here would be a good start), and be willing to redo your tank if you truly want the seahorses to have success.
As much as it's not as difficult to care for seahorses as most folks seem to think it is, it DOES require a certain amount of focus and specialization to successfully keep seahorses in the home aquarium environment.
As evidenced in this thread, it seems like you have an immediate rebuttal to any advice or direction given to you on this topic, so I really hope that you take this to heart as it is meant: From someone who really loves seahorse-keeping and wants to see them all in the best environments possible.
Simply having an impulse buy of some seahorses is not good for the livestock or for your tank. Please, ID the horses, do the REAL research, and adapt accordingly.... or.. find someone who IS ready to be keeping Reidi seahorses.