I know your question is whether or not a suspension fork can be added, but in most cases a suspension fork is totally unneccesary on a hybrid, and is just added weight that will slow you down. If you ride on pavement at all this added weight becomes a burden. The steel fork of the Giant, or better yet, a carbon fork, will serve you better and help to absorb road vibration and bumps. For what it would cost you for a new suspension fork you might be able to pick up a used hardtail mountain bike on craigslist. At the last swap meet I was at in June the hardtails were a dime a dozen, and many were reasonably/cheaply priced. Hybrids without suspension can handle most dirt and gravel MUPs just fine. So unless you're going to do single track, where a hardtail would serve you better anyway, I'd not add a suspended fork to a bike that's going to do pavement or MUPs.
The Escape is a nice hybrid choice.
