1. Can an infantry unit engage a block house even if the allied unit would get destroyed? If a Block House is engaged by an infantry unit that is destroyed, is the Block House discarded or does it stay on the battleground? Same thing for a road block...is it discarded?
If you engage a Static Defense and don't destroy it, it's discarded at the end of your turn.
2. There is an objective La Barquette Locks taht says "-2 to reinforcement total this turn." I'm assuming this means -2 on the recruitment phase. IF I have a Pathfinder with +2 and +2, does this Objective prevent me from acquiring any recruits this turn or is just a total of -2 applied to one of the pathfinder acquisitions?
You still have one +2 recruit as you only apply the -2 to one of them.