Unless you're grinding grass and flowers into your lights, there is no way for ADJ to know you used your stuff outdoors. But, they are stating the warranty is void to make you afraid. The main reason is that outside, you could be rained on. Water and electricity isn't a great combination. So, even if the fixture is grounded, it isn't made moisture-proof. We're talking safety.
But what if some nimrod turns on the fire suppression system/sprinklers inside? It's indoors. It's possible. Warranty still valid?
Go with your original plans. I've used my lights outside tons of times with no problem.
I'm guessing, but 2 Punch Pros would be sufficient, I'm guessing. Or you could double it. You're just concerned with washing with sufficient light to see any sheet music you may or may not have on hand.
Be smart, be safe, and use a power strip of some sort. Should the weater turn, kill your power, strike and run for shelter.
The LED fixtures are way light. If you do a T-bar or at least a tripod stand and an O-clamp with a safety pin, you're setting up super fast. Get a nice little DMX Operator 192, some good DMX cables(don't use mic cables even though they look the same) and you're good to go. Bet you have lights up and running in less than 10 minutes. Get some basic tools, such as an outlet tester. I also carry a multi-meter, ammeter and I test the voltage and draw, but that might be a big much. Get some Arriba cases and you should have portability, quick set and strike. Since you're going LED, you have low power draw. Sweet scenario!
On outdoor gigs, the people hiring me are responsible for all damage as a result of weather. When they see my rig, they realize that this might not be a good thing covering my possible expenses in the event of bad weather. So, they hire someone else. Fine with me, let their crap get ruined! Summer is much better for outdoor gigs anyways.
I have an outdoor gig scheduled for July. I'm using my 64B LED Pros for the stage.