More to the point, could a level 12+ mystic with the empath connection snipe someone in the other room with spells?
Blindsight (in the Universal Monster rules) says:
Invisibility, darkness, and most kinds of concealment are irrelevant, though the creature must have line of effect to a creature or object to discern that creature or object.
So if by 'the other room' you mean through a wall / closed door, then the answer is no unless the mystic has an ability that takes precedence.
I couldn't find that line when I text searched the Starfinder core rules, and blindsight (p.262) doesn't mention this. What page are you referencing?
I think the rules that Matthew Downie are mentioning are the universal monster rules for Pathfinder. Something similar to them should show up in the Alien Archive, I think.
So, until that gets released, I couldn't say one way or the other for certain.
Whether or not blindsight requires line of effect to detect something, you still need line of effect for a spell to target it.
If a weapon, spell, ability, or item requires an attack roll and has a range measured in feet, it normally requires that you (or whoever or whatever is using the ability) have a line of effect to the target to be effective (subject to GM discretion). A line of effect is a straight, unblocked path that indicates what an attack or ability can affect. A line of effect is blocked by a solid barrier that can stop the effect in question (such as a wall, for most effects), but it is not blocked by purely visual restrictions (such as smoke or darkness). You cannot have line of effect that exceeds planetary range, unless otherwise indicated.
You must have a clear line of effect to any creature or object you wish to target or to any space in which you wish to create an effect without an area.
Well dang, that's less I'm able to do. Good I know for sure now, though.
A follow-up question: even if I couldn't snipe someone with charm monster from behind a wall could I still sense them with blindsight (emotion)?