My understanding is Turtle Wax Ice and Meguiars D156 Synthetic Wax are both synthetic waxes (no natural carnauba wax but effectively a polymer sealant like Opti-Seal). Since Optimum doesn't test other companies products, there is no guarantee that these products can migrate through the Optimum Spray Wax like Opti-Seal. If you prefer to use these products, it might be best to reverse your process by applying synthetic wax as drying aid during ONR wash and follow up with Optimum Car Wax afterwards.
The only time to reverse the process is when you are in fact using a clay towel (or intend to use Opti-Seal which is confirmed to migrate through). This is because Optimum Spray Wax provides the best lubricity in order to minimize the risk of marring using the clay media (abrasive) as demonstrated by Yvan. If you intend to perform some form of paint correction after claying then Optimum Car Wax should not be necessary.
When layering natural carnauba wax, the recommended cure time between coats is 1-24 hours which will depend on environment and method of application as it requires time to dry as a hard layer before second layer is applied. Because Optimum Car Wax comes in spray form, I assume cure time in most cases would be 1 hour or less. Polymer sealants are different as they attempt to form a chemical bond with the paint and should be applied directly on bare paint wherever possible for maximum durability otherwise as you shed the shorter life carnauba wax, you will also loose the polymer sealant.