You'be posted in the Lounge, which is intended for casual creative discussion, but product-specific technical support is found in the product forum. I'll ask a moderator to move this thread to the Acrobat forum, where more people will see it.
Meanwhile, I'd offer that you can't do replacement of multiple graphics objects in Acrobat. If you already have a logo on each page, placed there by another program, you'd have to delete them all manually. Adding a new logo to each page can be accomplished with Headers and Footers, or with Watermarks, both of which can be applied to a range of pages.
Consider er whether you can go back to the original authoring document, which may offer an easier way to replace the logo en masse.
There's no easy way of doing that. If the logo is not overlapping with any other elements that you want to keep then you can use the Redaction tool to remove it from all pages (you can draw the redaction annotation on the first page and then duplicate it to the others using a script, like this one I've created: Custom-made Adobe Scripts: Acrobat/Reader -- Duplicate Annotations to Multiple Pages ), and then you can insert the new logo using the Add Watermark command, for example.
Another option is to use a button field to cover the old logo and set the button's icon as the new one. Then you can duplicate the button to the rest of the pages (notice that this will not get rid of the old logo, just cover it).
The best solution is to go back to the original file format used to create the PDF, edit it, and then generate a new PDF file, though.