No, the Tomahawk Excluder One Way Door E35 and other excluders do not come with mounting hardware since customer needs will vary.
Yes, you could potentially mount the Tomahawk Excluder One Way Door Model E35 from the interior of the structure if the opening into the structure were exactly the size of the trap (3.5 x 3.5 inches). The trap does need to sit horizontally or close to horizontal to function properly, allowing the one way door can close completely. If the opening is larger than the trap size, then you could potentially fill in the extra space with an exlusion material such as the Xcluder Single Roll.
The Tomahawk Excluder One Way Door Chipmunk & similar sized animals would not work for mice as they can get through holes 1/4 inch or larger.