So the lore for Visions of herecy and the fact that each charater has four skills would indicate that there are still two "Herecy" items to come. This blog is just some speculation as to what those might be.
So the first clue towards what they will be is that the four replacement skills are likely going to fill different roles, with a simple attack and a dodge already included. That leaves a signature move for [R] and an alternative attack for [M2). Judging from the skills of the existing characters there will probably be an AoE attack included.
Then the other clue is the possible names for the items. A "Visions" and "Strides" are both actions, that would indicate the other two will also be actions. Visions depicts an eye, and Strides is a leg. That would leave the rest to be organs or limbs as well, and since leg is included, one(potentially the M2) will likely be a hand. As eye already exists, perhaps tongue or teeth will be included. And finally the heart, as it is an important and symbolic organ, and the rest would be frankly silly. "Scent of Herecy" with a nose or "Regurgitation of Herecy" with a stomach? Can't really see that happening. Also I think it is safe to assume it won't be genitalia, this is not Binding of Isaac.
Bones would suggest a passive ability to me, unless...
The Items Themselves
The names for a hand could potentially be along the lines of: Clutches, Grasp, Signs (as in gesture) or Marks( as in "place a mark" or "brand"). Hand would also either mean a melee-attack with sharp claws or a hand signal that triggers something. Or maybe it is a energy wave á la Dragon Ball.
Then the mouth-one, either teeth (Chitter, Bites), lips (Kiss) or tongue (Words, Whispers). Bites and kisses would mean close range, but a sound would mean ranged, perhaps an AoE style attack. A roar, or a song? The mouth also eats, so lifesteal?
Then the heart. "Pulse of Herecy" sounds pretty neat, and it would also indicate a quake-like attack, and since it is a heart, healing is not ruled out.
Bones could mean bone spikes, jutting out of the characters themselves, and when activated stabbing out of them, or out of the ground.
This blog was written first on the other Risk of Rain wiki