newb from CA I've got a maverick with problems

Door panels kinda crumbled on me. Got it open.threaded Rod was gone. But I still can't figure out why it wouldn't unlock for now i just wont lock it.
So now I need to rebuild my front brakes. I want to do discs I've been reading and I came across the swap that uses toyota previa discs has anyone done this? The granada setup seems easier but have you seen the price of granada spindles there outrageous. im torn

so anyway first problem solved thanks for the tips ill be on here alot im sure