Populate a portfolio style grid with preview images of specific pages

I’m trying to achieve two things.

1. Allow a client to publish pages for each of their clients from the backend then publish that page and have the preview images populate a grid.

2. Prevent these pages from showing up in the general blog section and only populated the grid with preview images which link to the individual page of the client clicked.

Bonus: What is the best way to streamline this process if every client page will use the same format? If this is too much to explain here can you point me in the right direction? What am I looking for, forms? Trying to do this without a plugin.