Guess we'll find later on, hopefully comic con will shed more light on the scenario. At this point it's all up in the air, they could be sentient, they could not be, they could be willing, they could be used by someone other than Waller, it's all possible.
But based on the info we have and the concept of redemption, I'm still leaning on them being more sentient and lucid with the possibility that they may fall into a becoming more 'mindless', and I don't really see how them being completely mindless makes them assets to even Waller. Unless there's a way to actively and completely control them, this would just be an Umbrella corps sized disaster waiting to happen. Sentience means they would be able to comprehend the situation and the leverage being held against them at least, rather than just being rabid dogs with no consideration for Wallers (or anyone else's) goals or interests.
To be fair, all those questions could easily apply to the very concept of the Suicide Squad which is releasing villains back into the world for 'good behaviour' and also the villains trusting that they won't be used forever. If there is someone in control and using them, then their chance at 'life' is the reward and leverage, just as the chance of 'freedom' is leverage for the regular squad. The questionable nature of the concept is not exclusive.
Oooh now that's dark. Jason just using this situation to his advantage, and essentially being the guy who can let you live or die.