I can’t see Horace or Anri’s summon signs outside of the Deacons of the Deep fight.

I’ve had this issue too. Seems like about half the time, their summons are there, and half the time they aren’t. Definitely talk to them in firelink shrine after you meet them at the halfway fortress if you haven’t already. Not sure if it’s a bug, or some weird convoluted quest order that I haven’t figured out yet. But sometimes they just aren’t available for summoning even if you follow their quest.

Good news is that 1. Deacons are pretty easy comparatively, 2. If you need help, summon signs are usually plentiful in the cleansing chapel, and 3. Summoning them doesn’t give you any items/advance the quest, etc, so its pretty inconsequential.

/r/darksouls3 Thread