You only need one jack, the shock is not involved with spring at all.
Get some proper pentrating oil and leave to soak after several application. The one with a freezer effect works well. A slight tightening of the nut often helps to "crack" the rust as you are rotating nut on clean thread, not back onto rust part.
You need 19mm and 17mm ring spanners and sockets - that one socket AND ring spanner of each size to stop bolt rotating. Undo the top bolt first as the rear lower arm has some twist in it so with top free its easier to get off. Also the top mount has to "lift" slightly out of subframe cutout shape - it wont pull straight out sideways - its obvious why when its free.
Have a go! Did you look at the rear suspension guide?