No, they do not need the full version of Adobe Acrobat Pro.
They can use the latest version of Adobe Reader which is FREE.
You, however will have to have the full version of Adobe Acrobat Pro so you can create the form fields and most importantly, to be able to Enable Usage Rights for Adobe Reader
Once you have enable the usage rights, people can use the FREE Adobe Reader (download from Adobe's website) to edit the form fields you created and also save the PDF with these changes to send back to you .
Then use your Adobe Acrobat Pro to compare the documents.
So no printing and scanned is needed by your 200 contacts. They will be able to type their replies directly into the PDF Form Fields that you created and then send the original edited PDF back to you.