Rather than glues I would use the existing clamps, lugs, tuning rods.
can you put extra nuts and washers on the tensioning rods to clamp the case?
Cutting a hole will weaken the case substantially, are you going to sit on it? One of the links below shows them reinforcing the case.


Here are some other links I found.

Hole cut, then the drum reassembled ... drumhead/case/drumbarrel.
This looks like the Shakey Graves method.
http://m.imgur.com/a/M5d9E
(drag to see the pics)

There are instructions here "I cut a hole in the side of the case mounted an unused 14" snare, using the lugs on the resonant side...... " you'll need to read the rest of it and see the photos.
http://www.drumforum.org/index.php?/topic/122134-my-probably-over-the-top-suitcase-kit/ it is quite a recent thread, you might get extra tips if you join up.

Good video here, needed some inserts to make it strong enough to sit on.
http://www.drumforum.org/index.php?/topic/125647-suitcase-drum-and-or-other-alternatives/

Using case and pedal, no drum head.
http://www.drumforum.org/index.php?/topic/45950-suitcase-kit/

Several ideas, using a case and pedal, no drumhead.
http://www.drumforum.org/index.php?/topic/98510-who-has-suitcase-kits/

Tuning, might help when fastening it together.
https://www.youtube.com/watch?v=U3qMyc1G3XE

and... Case and foot , i.e. no drom, no pedal... -video -worth watching just for fun!
https://youtu.be/v4W92tIXhZQ

I hope you get back and post the results of whatever you decide on.