The Torpedo bottle is compatible with the Gorilla cage and in fact any XLAB cage. The only issue I see if you buy the Refill Kit, would be the zipties interfering with the bottle fitting securely. We haven't tested the Torpedo bottle with a cage ziptied as we have had poor experience of zipties breaking. Can you email me a picture of how you have it ziptied and I can give you a better answer?
There are 2 straw holes on top of the bottle for your location preference. One in the front above the refill area, and another behind the refill area. The straw that is included with the Refill Kit has a bite valve. If you prefer not to use the bite valve, you can cut it off. If you do, make sure you cut the bite valve first, before cutting the other end of the straw for length preference. The Dolphin tail on the top of the bottle allows you to tuck the straw when you are not using it.
For EFS liquid shots, as long as you dilute it there should be no issues in using EFS with the Torpedo.
XLAB - Aerodynamic Triathlon Accessories
Dawn to Dusk - Off-road Specific Storage Accessories http://www.XLAB-USA.com http://www.dawntodusk.bike