If your sole is out, I suspect a wood worker might be able to use the sole as a template to trim on oversized new piece down to the exact duplicate with a routing trimmer bit. And also cut the exact cut outs and access panels with the same system.I don't have a workshop with multitudes of tools anymore! I just have my garage floor for doing simple projects. I think I am going to seek a craftsman with a real shop for this little project!
You'll never cut plywood cleanly enough with a sabre saw that will come close to the finish a trimmer bit could do.