W116, Body and Interior Specific Aid

When it rains or snow collects on the car, my 85 300SD collects a BIG amount of water in the area behind the driver's seat on the floor. The passenger side (side of the battery tray) is completely dry. The sun roof seals are dry and need replacing. Could that be where the leak is coming from? I read there are drainage holes around the sunroof and they get plugged...? The car is 80% restored after sitting outside for about 13 years. The engine is a factory replacement, but after purchasing it from a wrecked condition, there were no written records of maintainence.

I will be replacing the front and rear rotors, should I also replace the bearings and seals? or is there a way to inspect them first?

While I have the calipers off, should I rebuild them? or is these a way to inspect them first?

Thanks,
Eric