Possibly. It all depends on the quality of the installer. The mortar is supposed to be struck (removed) from the inside. Key word: supposed. Normally what happens is that as the mortar is struck from the cavity side, a lot of it falls to the bottom. Or, if too much mortar is used, it squeezes out and just falls on it own. Either way, it blocks the bottom. The mesh is supposed to prevent the mortar from plugging the weep holes.I think the oozing mortar on the inside of brick would be the obstacle.
Hmm. I have a lot of experience with fishing wires and I'd try your first thought before trying the second one. If it was a hollow, empty wall, then OK, but full of insulation = difficult - unless you're really good.Maybe this is better?