It depends on what programs they do have. Recent versions of Acrobat allow for some editing of pdfs that have been made from InDesign documents but It's been my experience that text replacement is rather unreliable as far as actually doing much more than editing and/or replacing small areas of text. I wouldn't recommend it as an alternate page layout program. You can move around images and copy and paste images in from other documents. If you do try this make the pdf a pdf/X-4: 2010 with an Acrobat 8/9 compatibility (pdf 1.7).
Generally, when I've experienced a request like this it usually winds up being recreated in Microsoft Word since that is the program that most non-graphics people seem to all have. In those cases the documents had to be recreated in Word based on the InDesign original which really did defeat the purpose of using InDesign in the first place.
If you can provide more information about what programs the people you're dealing with have it would be a lot easier to help you.