I’ve always been fascinated by the unusual lifestyle, remarkable feeding habits, and appearance of sargassumfish, frogfish, anglers and the like. How wonderfully weird is it to have a fish that angles for other fish, tempting them within striking disputes by using its own built-in fishing rod and lure to attract them? Anglerfish and frogfish are indeed bottom dwellers that spend most of their time lurking motionless on the bottom or slowly "walking" along the substrate on stubby, limb-like fins, and they are not at all poisonous or venomous. They do not sting.
I’m not familiar with the dwarf frogfish, but everything you have heard about the eating habits of these amazing animals is based on fact. They have cavernous mouths with an incredible gape, bottomless appetites, and can easily consume prey as large or larger than themselves. (Some deep-sea anglers have distendable stomachs that can stretch to enormous portions, allowing them to swallow fish several times their own size, intact and whole.) Most other anglerfish lack the same sort of stretch-belly but they also manage to consume gargantuan meals by the simple expedient of allowing half of their latest victim to hang out of their mouths while they digest the other half. Sargassumfish and anglerfish are known to include seahorses on their menu, so I would have a very hard time trusting any sort of frogfish with my seahorses.
That doesn’t mean you have to do without the frogfish, but I would strongly suggest that you consider setting it up in a smaller specialty tank all its own. That would be the safest way to proceed and safely explore your interest in both the anglerfish and the seahorses.
Best wishes with all your fishes, Saint!