I'm doing my 01 Van trans this week. I would take the overdrive part to a trans shop to release the spring, install new clutches then re-install the spring aligning the splines with their line up shaft.
There is an updated pressure solenoid you should get too. I'm sure more of the experts will chime in on this.
Mine had nothing in the pan, but the magnet was about the size of a donut, a full 1/2 inch of very fine metal particals and what looked like moly lube. Haven't got it apart yet. I bought the factory complete overhaul kit less bands. Don't go cheaply on this.