When a holoecho marker blocks its bearer's LoF to an activated model, can its bearer declare any ARO that requires LoF? Of course the marker should block direct LoF of the bearer. But both marker and bearer should declare the same order and when bearer declares a skill require a roll, markers are removed. Or is there anything I misunderstand?
Markers do not obstruct LOF. LOF is checked at declaration for skills like BS Attack AND at Step 5/6. There's probably room for shenanigans as a result.
When you declare "BS Attack" as an ARO, the markers disappear, which then open up LoF for the Attack. It's a weird self-fulfilling prophecy in the rules, but it makes sense that a Holoprojector unit would be able to see through their own echoes via some sort of visor filter or whatever.
Holoechoes are considered real Troopers in regard to providing AROs, checking LOF, ~(from the rules wiki), so I don't think your first sentence is valid. However, I agree that there should be some room for this shenanigan, something like Delta57Dash said.
Troopers don't block line of fire, models and scenery do. A trooper in the Camouflaged state does not block LoF, for example. Which brings up the question if the player combines Holoecho and Holomask to deploy 3 models do they block LoF?
I've always taken the "treated as real troopers" bit to mean that holoechoes (whether markers or models) block LoF. Otherwise none of the three, whether the true model or one of the echoes, would block LoF. If you try to have only the (fake) holoechoes not block LoF, you open up all sorts of cans of worms, such as being able to indirectly ask if an echo is real by asking if it blocks LoF to a distant unrelated model.
