The rules on attacking creatures from hiding are:
When a creature can't see you, you have advantage on attack rolls against it. If you are hidden–both unseen and unheard–when you make an attack, you give away your location when the attack hits or misses.
Is your location "given away" to a blind & deaf creature that otherwise has no way to percieve you normally? What about if it is not the one being attacked?
(For clarity, the creature does not have truesight or blindsight or any other special senses. If it were next to you it could perceive you by touch, but in this situation it is not)
To that creature, you will be "unseen and unheard" before you make the attack, during it, and after it.
I think that this hinges on exactly what "give away your location" means. It could mean "all creatures in the combat know where you are", or it could mean "all creatures capable of perceiving you know where you are", or something else.