Knowing what this was like, I bought another subframe and built it up ready.
And then sold on the existing one. Of the 2nd hand frame I bought, on the bench / workmate, it was quite straight forward and only ended up having to cut a couple of bolts. Would not have liked to have done the work with it on the car.
As for the rear bushes, there is an extractor / installer tool.
I'd definitely go for the 2nd subframe method as I did, might cost a bit more but saves you so much grief. Swapping the subframe out as well on a disc braked version takes very little time. A bit more if you have drums as you have to piss about with brake lines and then brake bleeding.