you can achieve an OTA OS update on the TC55 with different tools.
An MDM, as you wrote, using StageNow (not pre-installed on the TC55 JB, so you need a first step with Rapid Deployment) or using the EMDK.
All these methods, under the hood, use the Power Profile:
Yes, with Stagenow is possible, just read a barcode with previous configuration on the PC
OS Updates OTA is possible with both AirWatch and SOTI MobiControl. Although the process to configure this is different for each the underlying mechanism is the same.