Yes it is rigid. I put bags on top when I pack the truck with out any worries. I think the Halon would fit nicely.
I have the SKB Rectangle bow case (love it), and it will accommodate any bow. It even has extra space to pack other items.
The one I have is the Freedom. The cheaper version. Doesn't quite work with the Halon. The limbs are pretty wide.
For 99% of my bow transport, I have a Game Plan Pass Thru case that was purchased in 2010 and going strong nearly 6 years later. My kids bought a Plano Parallel Limb hard case for me a couple years ago for Father's Day and it has yet to see daylight from my basement. It is a nice case and set up to safely house my Prime Rival, but too big a bulky for regular shooting or hunting use. It will certainly see use on my next out-of-state adventure, but it mostly sits.......
I've used this Flambeau for the past 3 years and it's been great. Holds 12 arrows too instead of the typical 6 I usually. Only $35 on Gander Mountain!
This case looks great but I can't find an arrow case on their website to go with the bow case. They say it's not included but you'd think they would sell an arrow case to go with it, even if you have to buy it separate.