Piece of Cake
Brother of The Benz, morrib
You've identified the rascals to a tea.
You've also identified the fastening items.
What is remaining is removing the door panels.
This can be somewhat tricky.
I would suggest looking at a Chassis Manual for the little tricks in removing the window/power seat escuhion. The panel too has it's own way of being removed. There may be a DIY forum as well.
The door checks are relatively cheap, mail order $13-14.00, from a dealer, $24-26.00.
Try Fast Lane for an even better price and delivery.
My 1987 300E has had these replaced this year, all four. The left rear door stuck open when the check broke. I decided to replace them all.
Happy Trails Beep Beep from The Spiderman in Houston!!!