I think you'll be struggling for a schematic. What I have seen so far is evidently wildly wrong, like the one below.
Shouldn't be too hard to note down the values and replace with Alcap 50V NP types.
Sometimes you have to be a light unto yourself with these things. 3 ways, here with an ABR AFAIK, tend to follow a pattern: SEAS-3-Way-Classic
I usually photograph the reverse of the PCB, flip it 180 degrees in a paint program for a mirror image and trace the wires and components against the top side.
Old speakers often benefit from fresh metal on the connectors, and checking polarity on bass particularly. It can often get flipped by the ham-fisted. Easy way to check bass polarity is to face the speakers together and see if it disappears as is the case with reverse polarity. Basses often have broken or frayed tinsel leads, which is a relatively easy repair too if you order the right stuff and lead solder and maybe some epoxy resin.
Do get back if you make some progress. It helps others.
