The reliable way to hire a tradesperson

My daughter lives in a terraced house fronted with engineered brick. The whole frontage needs repointing and several tradesmen have said it should be pointed with lime mortar. Since the bricks are non-porous and don’t breath, why does the pointing need to be lime and breath? Surely the pointing mortar should have similar properties to the brickwork.?

I have identified dry rot in one room caused by a lack of ventilation ( new air bricks and replacement timber is needed as well as a chemical treatment). The plaster is very sound and there is no moisture according to a contractors moisture reader. Do I need to hack off the plaster nonetheless?

I can feel a draft coming from under the skirting board and it is coming away from the wall (i think previous attempt at insulating and/or for wires to be put behind) taking it off to try to insulate it and attach it flush to the wall, the plaster behind is non existent and the bricks behind are wet to the touch. not sure what the best way to proceed is.