Since when has the Echo given us foresight, though? It lets us see past events, not future ones... For it to even have had any function in the events of 2.55, she'd also have to have been in contact with those involved to use Echo hacks to gain any insight into what was going on and it would have to have been on the spot, which doesn't give a lot of time to recover and set a clear course of action to aid us... It seems more likely to me that she just figured something was up, presumably Crystal Braves were setting up to secure the area, and were I her, I'd find it odd if my brothers militia was hanging around and he'd never informed me of it... Not hard to then be prepared for them, then send aid when events take a turn... Didn't Urianger also put in special protective measures following Lahabrea/Livia storming the place way back? Seems much more likely to me that the Waking Sands was just targeted after we entered the trap, but not before it was sprung... That gives her enough time to piece together what's happening and send the small amount of aid we received from her...
I absolutely want her to summon Phoenix-Egi though, I think that could make for a fairly nice climatic revival of someone, she'll probably have to have her brother there too though, for another use of the worlds most impractical book...
As far as I'm aware, we don't actually have any confirmation who, but like I said, Nabriales was watching and claimed "Lahabrea will be pleased", that implies it was Lahabreas plan, not his. What's more, Lahabrea did pretty much the same thing with Thordan, then you should also consider the whole "of this world" thing and how that gains Lahabrea and Elidibus additional freedoms that Nabriales and the others lacked at that point in time... Lastly, if you tie Lahabrea back to XII, which his name is definitely referencing, then he should have some association with Ice, and indeed does, based on the ARF battle...