Sorry if I'm not accurate here, but I'm not where my 126 manual is...regarding your lower body cladding, do you mean the plastic trim around the bottom of the fenders and doors? If so, there is a slightly different procedure for each piece, like front fenders, front doors, and rear doors. I've changed the trim on the right front fender and removed/replaced the front right door. The removal of left and right sides is the same. Please confirm if these are the pieces and I'll check back over the weekend and post instructions from the manual, unless someone else chimes in of course.
Yes, you can re-use the clips.

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1986 560SL
2002 Toyota Camry
1993 Lexus