Bryn,
Google is funny about the usage of the "Gmail" email client in kiosk and work profile enrollments. Even if you have no intention of using this, there can be a compliance error as Eamonn has advised.
I understand the client does not want personal accounts on the device. however if you do have clients that are using email ,as a rule of thumb when I configure Samsung devices where email is going to be used, I like to push the Samsung email,contacts, calendar clients and configure them as opposed to using the native gmail client. After many years of doing this I have found it is a much better experience for the end user.
Further, you have not set a strong enough passcode on the device, based on the policy you configured for Kiosk Mode for this device. This will trigger the compliance alert as well.
I am more than happy to jump on a call with you if you would like to chat about this.
SIncerely,
Mitch Lauer
ConnecTel Wireless
412-339-5765
(5 year IBM Champion)