1)
Well the first one... just make it so it isnt a building like the normal ones, dont know if there is a option or a trigger for the normal race buildings, but dont think so, so use a shop or something like it as the building, but why you want to remove it? So they always will go the same place? If then make a trigger taht places the rally point every 3 sec..
2)
Dont understand what you mean? Do you mean the describtion for building building or for the summon item one or... ?