Yes a set of coilovers will fit into an ae71, but its best to use the 71 strut tops, and its neccesary to use ra40 or 86 steering arms
Yes a set of rear coilovers will fit but you have to take into account that strenghtening will be needed around the shock top as its not engineered to have all the suspension force in one small area
Yes a front strut brace will fit onto a 70 or 71 and a rear one will not