I see a couple issues with your plan. You may find your bat mix is a bit hot for auto seedlings. Autos tend to be a bit nutrient sensitive, especially when they are young. Better with a lighter mix for seedlings, then the more potent mix once they are established. That could also be contributing to the delay in sexing. I've not heard of any issues with Easy Ryder not showing sex, so just give them a bit more time. The extra bulb you are using for heat could also be an issue. While autos aren't as sensitive to light leaks during lights off as photos are, you could still be running the risk of having your plants go hermie on you. Better if you use a small space heater instead of the light.
Also, mixing photos and autos in the same grow space can be problematic. Autos do best on a 20/4 light schedule. If you reduce the lights to 12/12 you will sacrifice a lot of yield from the autos. Best to either scrape the photo plant for now or remove it daily to a totally dark place after 12 hours.