How to go about replacing a door

[Kyohe]

Hello, I have a 1980 300td with some heavy damage to the doors on the right side. I was thinking the best course of action was to try to replace them. I have some questions about doing that though.

How do you go about disconnecting / reconnecting the electrical and vacuum tube in the accordion at the door hinge? Do you have to cut them or do they have connectors designed to be pulled apart?

Is there a way to test the power windows without hooking up power? Should I try taking a battery or something to the junk yard to try to test them?

Can I use w123 sedan doors at all on my wagon?

Any other advice or comments would be greatly appreciated. I'm hoping against hope to get solid rust free doors in China Blue. Thanks.