Spotlight / Targeting a holoecho

I think as has been concluded with mines and mission objectives being put into Targeted State previously; Targeted has no real effect on a Holoecho because it is not a Trooper.

 

No it's not cancelled, because as you note the Holoecho doesn't have any of the cancellation clause' triggered, but your opponent will know it's a Holoecho when you don't make a Guts Roll.
Now, if your opponent isn't paying attention to the Guts Roll mechanic, I don't know how that works mechanically with declaring the Guided ammo attack, that is to say whether the information that your opponent is unable to declare Guided against the target is available before or after they declare the BS Attack.

To re-iterate, this is information derived from consensus and previous answers relating to The Grid ITS mission. I don't think, and I can't find, that it has been discussed in context of Guided ammo, but Guided ammo are Anti-Material and The Grid had destructible Antennas that first had to be Targeted, so it should have come up that those Antennas were targetable by Guided ammo and as far as I know, it hasn't.